Multi-color light emission apparatus with organic electroluminescent device

ABSTRACT

This invention provides a multi-color light emission apparatus wherein a transparent inorganic oxide substrate (4) is disposed between an organic EL device (1) and a fluorescent layer (3) in such a manner as to arrange the fluorescent layer (3) with a gap with the organic EL device (1), and the organic EL device (1) is sealed by sealing means (5) between the transparent inorganic oxide substrate (4) and a support substrate (2). The invention provides also a multi-color light emission apparatus wherein a transparent insulating inorganic oxide layer (12) having a thickness of 0.01 to 200 μm is interposed between the fluorescent layer (3) and the organic EL device (1). In this way, light emission life and angle-of-view characteristics can be improved.

FIELD OF THE INVENTION

This invention relates to a multi-color light emission apparatus and amethod for producing thereof. More specifically, this invention relatesto a multi-color light emission apparatus suitable for use inmulti-color or full-color thin-type displays and a method for producingthe multi-color light emission apparatus.

DESCRIPTION OF THE BACKGROUND ART

An electroluminescence device (hereinafter called "EL device") ischaracterized in exhibiting high visibility due to self-emission and inhaving excellent impact resistance because of being completely solid. Atpresent, variable EL devices using an inorganic or an organic compoundas the emitting layer are proposed and attempts have been made to putthem to practical use. One of the EL devices which has been realized isapplied as a multi-color light emission apparatus.

Such a multi-color light emission apparatus includes an apparatusproduced by combining a color filter of three primary colors (red,green, and blue) with a white-light emitting inorganic EL device and anapparatus produced by patterning inorganic EL devices of three primarycolors in order to position the EL devices of three primary colorsseparately on the same plane and thereby to emit light (Semicond. Sci.Technol. 6 (1991) 305-323) However, there is the problem that the effectof emitting light of each color is limited to 33% of the white light atmost if the white color is resolved by the color filter of three primarycolors. Further, EL devices which themselves can efficiently emit whitelight have still not been attained at present.

On the other hand, a photolithography process is used for patterning ELdevices. However, it is known that the efficiency and stability of ELdevices are greatly reduced in such a wet process.

It is common knowledge that, among EL devices, organic EL devices arepromising as highly intense and efficient light emitting devices. Inparticular, because the light emitting layer is an organic layer, it ishighly probable that various emitting colors are produced by themolecular design of organic compounds. Such an organic EL device isexpected to be one device which can be used in practice in a multi-colorlight emitting apparatus.

However, these organic EL devices have the drawback that chemicalfactors such as external steam, oxygen, organic compound gas, and thelike cause deterioration of the EL devices such as reduction inluminance accompanied by the occurrence of dark spots and the like andthese devices tend to be destroyed from physical (mechanical) factorssuch as heat, impact, or the like since the EL devices are composed of alaminate of low molecular organic compounds.

Therefore, the method for separately disposing each of the organic ELdevices, which emit lights of three primary colors (RGB), on the sameplane can be used in a wet process or a process including heat treatmentsuch as a photolithography process only with difficulty.

In order to solve such a problem, disclosed is a color EL displayapparatus (see Japanese Patent Application Laid-open No. 40888/1989).This apparatus is, as shown in FIG. 8, characterized in that an ELemitting layer 1b sandwiched between a lower electrode 1c and a lighttransmitting upper electrode la is disposed on a substrate 2, the ELlight which is output via the light transmitting electrode la isexternally output from a transmitting substrate 8 via a color filter 9installed on the transmitting substrate 8, the color filter 9 facing thetransmitting electrode 1a.

This apparatus has, however, the disadvantage that the luminance of thelight of each color is reduced to one third of the EL light by the colorfilter. Also, because the EL device faces the color filter, the lightemission life of the EL device is invariably reduced by aqueous vapor,oxygen, gas from organic monomers, low molecular components, and thelike generated by the color filter.

To solve these problems, lately disclosed is a technique in which afluorescent layer absorbing light emitted from an organic EL device andemitting visible fluorescent light is installed in the position(laminated or in parallel) corresponding to the emitting portion of theorganic EL device (see Japanese Patent Application Laid-open No.152897/1991). This technique ensures that the light of a blue orblue-green color emitted from the organic EL device is converted into afluorescent light which is visible light of a longer wave length. Thistechnique is utilized in a multi-color (three primary colors) lightemission apparatus in which fluorescent layers capable of converting theblue or blue-green color into a green or red color are separatelydisposed on a flat plane (see Japanese Patent Application Laid-open No.258860/1993).

The installation of the fluorescent layer has the advantage thatmulti-color light emission which is higher in efficiency than in thecase of installing a color filter is expected. Specifically, if thefluorescent layer especially for converting into a green color isexpected to absorb 80% or more of the blue color light emitted from theorganic EL device, a variety of fluorescent materials capable ofemitting fluorescent light at an efficiency of 80% or more are known.Assuming both the light absorbing efficiency and light emittingefficiency of the fluorescent layer to be 80%, it is estimated that theblue light of the organic EL device can be converted into visible lightwith a long wave length at a yield of 64%.

A multi-color light emission apparatus can be realized using an organicEL device and a fluorescent layer in the above manner. Japanese PatentApplication Laid-open No. 258860/1993 proposes the following structurefor the multi-color light emission apparatus.

As shown in FIG. 15, fluorescent layers 3R, 3G absorbing the lightemitted from an organic EL device and emitting a green color and redcolor respectively are separately disposed on a transparent substrate 11on the same plane. A polymer and/or cross-linking compound of an organicmonomer or oligomer and a transparent insulating rigid plane layer(protective layer) 7 produced by a sol-gel glass method are laminated onthe transparent substrate 11 including the fluorescent layers 3R, 3G byspin casting. A transparent electrode 1a of the organic EL device isdisposed on the plane layer 7.

Disclosed as other structures are a structure in which the transparentand insulating flat rigid elements is simply placed on the surface ofthe fluorescent layer instead of being laminating on the fluorescentlayer by spin casting and a structure in which the fluorescent layer isaffixed to the back face of the hard element exhibiting the functions ofa flat plane layer instead of affixing the fluorescent layer to thesurface of the substrate. However, it is reported that the structureshown in FIG. 15 is preferable.

The structure shown in FIG. 15, however, has the problem that the lightemission life of the organic EL device is reduced by aqueous vapor,oxygen, gas from monomers and the like which are adsorbed to or includedin the organic compound of the flat plane layer in a slight amountwhereby the emission is indispensably non-uniform, because thetransparent electrode of the organic EL device is only disposed on thesame flat layer composed of the polymer and/or cross-linking compound ofan organic monomer or oligomer.

Also, a high temperature treatment at 400° C. or more is generallyrequired for the production of the flat plane layer in the sol-gel glassmethod. This causes the deterioration of the organic fluorescent layer.If the sol-gel glass flat plane is produced by heat treatment (up to themaximum temperature of around 250° C.) which never causes thefluorescent member to deteriorate, there is the problem that the lightemission life of the organic EL device is greatly reduced for the samereason as above because water or organic compounds remain.

Also, clear explanations about the hard member in the other structuresare not necessarily sufficient.

On the other hand, disclosed is a method in which a glass plate with acolor filter formed by printing is disposed under the back face of aglass substrate of an inorganic EL device (see Japanese PatentApplication Laid-open No. 119494/1982).

However, a reduction in the emitting efficiency caused by the colorfilter is easily predicted in this method. Also, since the organic ELdevice is produced independently of the color filter, camber anddistortion of the substrate occur so that the EL device cannot bemanufactured in a stable manner, if, for example, the thickness of thesubstrate of the organic EL device is not increased (around 700 μm ormore). As a result of the increase in the thickness of the substrate,the gap between the color filter and the EL device increases, wherebyemitted light of a color other than the desired emitted colors leaks toremarkably narrow the angle of view when multi-color light is emitted.

This invention has been achieved in view of this situation and has anobject of providing a multi-color light emission apparatus using anorganic EL device having superior light emission life and excellentcharacteristics in the angle of view and a method for manufacturing themulti-color light emission apparatus in a stable and efficient manner.

DISCLOSURE OF THE INVENTION

The above object can be attained in a first invention by the provisionof a multi-color light emission apparatus comprising a supportsubstrate, an organic electroluminescence (EL) device disposed on thesupport substrate, and a fluorescent layer disposed corresponding to atransparent electrode or electrode of the organic EL device to absorbthe light emitted from the organic EL device and to emit visiblefluorescent light, wherein a transparent inorganic oxide substrate onwhich a fluorescent layer is placed is disposed between the organic ELdevice and the fluorescent layer in such a manner as to provide a gapbetween the fluorescent layer and the organic EL device, and the organicEL device is sealed by a sealing means between the transparent inorganicoxide substrate and the support substrate.

In preferred embodiments, the fluorescent layers are separately disposedon the transparent inorganic oxide substrate on the same plane;

a protective layer of the fluorescent layers and/or a transparentsubstrate are further disposed on the fluorescent layer;

the plate thickness of the transparent inorganic oxide substrate is in arange of from 1 to 200 μm; and

the transparent inorganic oxide substrate is made of a transparent glassplate.

The above object can be attained in a second invention by the provisionof a multi-color light emission apparatus comprising a transparentsupport substrate, fluorescent layers separately disposed on thetransparent support substrate on the same plane, and an organicelectroluminescence (EL) device disposed on or above the fluorescentlayers, the fluorescent layers being disposed corresponding to atransparent electrode or electrode of the organic EL device so that eachof the fluorescent layers absorbs the light emitted from the organic ELdevice and emits different types of visible fluorescent light, wherein atransparent and insulating inorganic oxide layer with a thickness offrom 0.01 to 200 μm is interposed between the fluorescent layer and theorganic EL device.

In preferred embodiments, a transparent protective layer of thefluorescent layers and/or a transparent adhesive layer are disposedbetween the fluorescent layer and the transparent and insulatinginorganic oxide layer;

the transparent and insulating inorganic oxide layer is made of atransparent and insulating glass plate;

the transparent and insulating inorganic oxide layer is made from one ormore compounds selected from a group consisting of silicon oxide,aluminum oxide, and titanium oxide; and

the transparent and insulating inorganic oxide layer is produced byforming a film of one or more compounds selected from a group consistingof silicon oxide, aluminum oxide, and titanium oxide on at least one ofthe surface or back face of a transparent and insulating glass plate.

The above object can be attained in a third invention by the provisionof a method for manufacturing a multi-color light emission apparatus byseparately disposing, on a transparent support substrate, fluorescentlayers absorbing the light emitted from an organic EL device andemitting different visible fluorescent light on the same plane and bydisposing the organic EL device on or above the fluorescent layer sothat a transparent electrode or electrode of the organic EL devicecorresponds to the fluorescent layer, comprising:

(A) a step of separately disposing the fluorescent layers on thetransparent support substrate on the same plane;

(B) a step of disposing a transparent protective layer of thefluorescent layers and/or a transparent adhesive layer on thefluorescent layers and on the transparent support substrate on which thefluorescent layers are separately disposed;

(C) a step of bonding a transparent and insulating glass plate with athickness of from 1 to 200 μm, in which a transparent electrode isformed or is to be formed, or bonding a member produced by forming afilm made of one or more compounds selected from a group consisting ofsilicon oxide, aluminum oxide, and titanium oxide on at least one of thesurface or back face of a transparent and insulating glass plate, to thetransparent protective layer of the fluorescent layers or to atransparent adhesive layer; and

(D) a step of laminating an organic compound layer and electrodes of theorganic EL device in order on the glass plate in which the transparentelectrode is formed.

The first to third inventions can provide a multi-color light emissionapparatus using an organic EL device having superior light emission lifeand excellent characteristics in the angle of view and a method formanufacturing the multi-color light emission apparatus in a stable andefficient manner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic and typical cross section of an embodiment of themulti-color light emission apparatus (first invention) of the presentinvention.

FIG. 2 is a schematic and typical cross section of the multi-color lightemission apparatus (first invention) of the present invention showinganother embodiment using a protective layer of the fluorescent layers.

FIG. 3 is a schematic and typical cross section of the multi-color lightemission apparatus (first invention) of the present invention showing anexample using a transparent substrate.

FIG. 4 is a schematic and typical cross section of the multi-color lightemission apparatus (first invention) of the present invention showing afurther embodiment using a fluorescent layer separately disposed.

FIG. 5 is a schematic and typical cross section of the multi-color lightemission apparatus (first invention) of the present invention showing anexample using a color filter and a black matrix.

FIG. 6 is a schematic and typical cross section of the multi-color lightemission apparatus (first invention) of the present invention showing another embodiment using a protective layer of the fluorescent layers anda transparent substrate.

FIG. 7 is a schematic and typical cross section of a comparativeexample, relative to the first invention, wherein a fluorescent layer isdisposed in the same side as an organic EL device on a transparent glasssubstrate.

FIG. 8 is a schematic and typical cross section of an example of aconventional multi-color light emission apparatus.

FIG. 9 is a schematic and typical cross section of an embodiment of themulti-color light emission apparatus (second invention) of the presentinvention.

FIG. 10 is a schematic and typical cross section of the multi-colorlight emission apparatus (second invention) of the present inventionshowing another embodiment using a transparent adhesive layer.

FIG. 11 is a schematic and typical cross section of the multi-colorlight emission apparatus (second invention) of the present inventionshowing a further embodiment using a transparent adhesive layer and atransparent protective layer of the fluorescent layers.

FIG. 12 is a schematic and typical cross section of the multi-colorlight emission apparatus (second invention) of the present inventionshowing a still further embodiment using a transparent protective layerof the fluorescent layers.

FIG. 13 is a schematic and typical broken view of the multi-color lightemission apparatus (second invention) of the present invention showing astill further embodiment using a color filter and a black matrix.

FIG. 14 is a schematic and typical cross section of the multi-colorlight emission apparatus (second invention) of the present inventionshowing a still further embodiment using a transparent adhesive layer, aprotective layer of the fluorescent layers, and two transparent andinsulating inorganic oxide layers.

FIG. 15 is a schematic and typical cross section of an example of aconventional multi-color light emission apparatus.

DETAILED DESCRIPTION OF THE INVENTION AND PREFFERED EMBODIMENTS

The multi-color light emitting apparatus of the invention and a methodfor manufacturing thereof will now be explained in more detail.

The organic EL multi-color light emission apparatus of the presentinvention must have a structure in which the light (especially a bluecolor or blue-green color) emitted from an organic EL device isefficiently absorbed by a fluorescent layer, without light reduction andlight scattering, and in which a fluorescent light emitted from thefluorescent layer is externally output without light reduction and lightscattering.

I . Multi-color Light Emission Apparatus (First invention)

From the above points of view, the first invention is specificallyexemplified by the following structures (1)-(3), which are respectivelyshown in FIGS. 1-3. Incidentally, a fluorescent layer may convert thelight emitted from an organic EL device into light of a wave lengthlonger than that of the light emitted from the organic EL device.

(1) Support substrate 2/organic EL device 1 (electrode 1c/organiccompound layer 1b/transparent electrode 1a)/gap 6/transparent inorganicoxide substrate 4/fluorescent layer

(2) Support substrate 2/organic EL device 1 (electrode 1c/organiccompound layer 1b/transparent electrode 1a/gap 6/transparent inorganicoxide substrate 4/fluorescent layer 3/protective layer 7 of thefluorescent layers)

(3) Support substrate 2/organic EL device 1 (electrode 1c/organiccompound layer 1b/transparent electrode 1a/gap 6/transparent inorganicoxide substrate 4/fluorescent layer 3/transparent substrate 8)

In the apparatus of the present invention, the organic EL device 1 issealed by a sealing means 5 formed by bonding the transparent inorganicoxide substrate 4 to the support substrate 2, for example, using anadhesive.

Also, in the structures (1) to (3), as shown in FIG. 4, the fluorescentlayers 3 which emit rays of fluorescent light of different colors areseparately disposed on the same plane to obtain emitted light of thethree primary colors (RGB). In this case, the plate thickness of thetransparent inorganic oxide substrate 4 is preferably in a range of from1 μm to 200 μm. Further, as shown in FIG. 5, a color filter 9a may bearranged on each of the fluorescent layers 3 to control the fluorescentcolors and thereby to promote the color purity. Also, a black matrix 9bmay be disposed between the fluorescent layers or color filters toprevent light leakage and thereby to promote the visibility ofmulti-color emitted light.

Next, the multi-color light emission apparatus of the present inventionwill be illustrated in more detail in terms of each structural element.Materials used for these structural elements are not limited to thematerials described hereinafter which correspond to the lowest demandsof these elements.

1. Organic EL Device

As the organic EL device of the present invention, it is preferable touse organic EL devices which emit lights ranging from near ultravioletlight to light of a green color, more preferably a blue-green color. Thefollowing structures are exemplified for the organic EL device of thepresent invention to obtain such a light emission.

These structures comprises fundamentally an emitting layer composed ofan organic compound which is sandwiched between two electrodes (anode)and (cathode) and other layers may be interposed between them asrequired. Typical structures for the organic EL device used in thepresent invention are as follows:

(1) Anode/emitting layer/cathode;

(2) Anode/positive hole injection layer/emitting layer/cathode;

(3) Anode/emitting layer/electron injection layer/cathode; and

(4) Anode/positive hole injection layer/emitting layer/electroninjection layer/cathode.

(a) Anode

An anode using, as an electrode material, metals, alloys, electroconductive compounds, and mixtures of these which have a high workfunction (more than 4 ev) are preferably used. Given as examples of suchan electrode material are metals such as Au and electro conductivematerials such as CuI, ITO, SnO₂, and ZnO. A thin film of each of theseelectrodes is formed by means of vapor deposition, sputtering, or thelike to produce the anode.

If the light emitted from the emitting layer is taken out of the anodein this manner, it is desirable that the transmittance by the anode ofthe emitted light be more than 10%. In this case, the anode correspondsto the transparent electrode. Also, the sheet resistance of the anode ispreferably less than several hundreds Ω/□. The thickness of the anode isusually from 10 nm to 1 μm, preferably from 10 nm to 200 nm, althoughthis depends on the material used.

(b) Emitting layer

Major emitting materials for the organic EL device are organiccompounds. As specific examples of the organic compounds used for theemitting layer, the following compounds are given, depending on thedesired color.

First, emitted light of ultraviolet to the violet color region can beprepared using the organic compounds represented by the followinggeneral formula. ##STR1## wherein X represents the following compound.##STR2## wherein n denotes 2, 3, 4, or 5, and Y represents the followingcompound. ##STR3##

In the above compounds, a phenyl group, phenylene group, and naphthylgroup may be substituted with one or more alkyl groups having from 1 to4 carbon atoms, alkoxy groups, hydroxyl groups, sulphonyl groups,carbonyl groups, amino groups, dimethylamino groups, and diphenylaminogroups. Also, these groups may be combined to form a saturatedfive-membered ring or a saturated six-membered ring. Further, it ispreferable that the phenyl group, phenylene group, and naphthyl group besubstituted at a para position so as to be easily substituted and toform a smooth deposition film. The compounds represented by thefollowing formula are given as examples of the compounds substituted ata para position. Among these compounds, p-quarterphenyl derivatives andp-quinquephenyl derivatives are preferable. ##STR4##

Next, given as examples of the organic compounds used for producingemitted light of a blue color to a blue-green color or a green color arefluorescent bleaching agents such as a benzothiazole type,benzoimidazole type, and benzoxazole type; metal chelated oxinoidcompounds, and styryl benzene type compounds.

Illustrating specific compounds, for example, the compounds disclosed inJapanese Patent Application Laid-open No. 194393/1984 are exemplified.Among these, typical examples are fluorescent bleaching agents includinga benzoxazole type such as2,5-bis(5,7-di-t-pentyl-2-benzoxazolyl)-1,3,4-thiadiazole,4,4'-bis(5,7-di-t-pentyl-2-benzoxazolyl)stilbene,4,4'-bis(5,7-di-(2-methyl-2-butyl)-2-benzoxazolyl)stilbene,2,5-bis(5,7-di-t-pentyl-2-benzoxazolyl)thiophene,2,5-bis(5-α,α-dimethylbenzyl-2-benzoxazolyl)thiophene,2,5-bis(5-7-di(2-methyl-2-butyl)-2-benzoxazolyl)-3,4-diophenylthiophene,2,5-bis(5-methyl-2-benzoxazolyl) thiophene, 4,4'-bis(2-benzoxazolyl)biphenyl, 5-methyl-2- 2-4-(5-methyl-2-benzoxazolyl)phenyl!vinyl!benzoxazole, 2-2-(4-chlorophenyl)vinyl!naphtho 1,2-d!oxazole, and the like;benzothiazole type such as 2-2'-(p-phenylenedivinylene)-bisbenzothiazoleand the like; and benzoimidazole type such as 2- 2-4-(2-benzoimidazolyl)phenyl!vinyl!benzoimidazole, 2-2-(4-carboxyphenyl)vinyl!benzoimidazole, and the like. In addition,other useful compounds are enumerated in Chemistry of Synthetic Dyes,628-637, P640, (1971).

As the above-mentioned chelated oxinoid compounds, the compoundsdisclosed in Japanese Patent Application Laid-open No. 295695/1988 canbe used. Among these, typical examples are 8-hydroxyquinoline type metalcomplexes such as tris(8-quinolinol) aluminum, bis(8-quinolinol)magnesium, bis(benzo f!-8-quinolinol) zinc,bis(2-methyl-8-quinolinolate) aluminum oxide, tris(8-quinolinol) indium,tris (5-methyl-8-quinolinol) aluminum, 8-quinolinol lithium, tris(5-chloro-8-quinolinol) gallium, bis(5-chloro-8-quinolinol) calcium,poly zinc(II)-bis(8-hydroxy-5-quinolinonyl)methane!, and the like anddilithium epinetridione.

As the above-mentioned styryl benzene type compounds, the compoundsdisclosed in the specifications of EPCs No. 0319881 and No. 0373582 canbe also used. Typical examples of these styryl benzene type compoundsare 1,4-bis(2-methylstyryl)benzene, 1,4-bis(3-methylstyryl)benzene,1,4-bis(4-methylstyryl)benzene, distyrylbenzene,1,4-bis(3-ethylstyryl)benzene, 1,4-bis(2-methylstyryl)-2-methylbenzene,1,4-bis(2-methylstyryl)-2-ethylbenzene, and the like.

Further, distyryl pyrazine derivatives disclosed in Japanese PatentApplication Laid-open No. 252793/1990 can be used as the material forthe emitting layer. Typical examples of these derivatives are2,5-bis(4-methylstyryl)pyrazine, 2,5-bis(4-ethylstyryl)pyrazine, 2,5-bis2-(1-naphthyl)vinyl!pyrazine, 2,5-bis(4-methoxystyryl)pyrazine, 2,5-bis2-(4-biphenyl)vinyl!pyrazine, 2,5-bis 2-(1-pyrenyl)vinyl!pyrazine, andthe like.

In addition, the polyphenyl type compounds disclosed in thespecification of EPC No. 0387715 can be used as the material for theemitting layer.

Other than the above-mentioned fluorescent bleaching agents, metalchelated oxinoid and styryl benzene, the following compounds can be usedas the material for the emitting layer:

12-phthaloperinone (J. Appl. Phys., Vol 27, L713, (1988)),1,4-diphenyl-1,3-butadiene, 1,1,4,4-tetraphenyl-1,3 butadiene (Appl.Phys. Lett., Vol 56, L799, (1990)), naphthalimide derivatives (JapanesePatent Application Laid-open No. 305886/1990), perillene derivatives(Japanese Patent Application laid-open No. 189890/1990), oxadiazolederivatives (Japanese Patent Application Laid-open No. 216791/1990 oroxadiazole derivatives disclosed by Hamada et al. at the conference ofAppl. Phys), aldazine derivatives (Japanese Patent Application Laid-openNo. 220393/1990), pyraziline derivatives (Japanese Patent ApplicationLaid open No. 220394/1990), cyclopentadiene derivatives (Japanese PatentApplication Laid-open No. 289675/1990), pyrrolopyrrole derivatives(Japanese Patent Application Laid-open No. 296891/1990), styrylaminederivatives (Appl. Phys. Lett., Vol 56, L799, (1990)), coumarine typecompounds (Japanese Patent Application Laid-open No. 191694/1990), andmacromolecular compounds described in the International DisclosureOfficial Gazette WO90/13148 or Appl. Phys. Lett., Vol 58, 18, P1982(1991).

In the present invention, as the materials used for the emitting layer,aromatic dimethylidine type compounds (compounds disclosed in thespecification of EPC No. 0388768 or Japanese Patent ApplicationLaid-open NO. 231970/1991) are preferably used. Specific Examples ofsuch compounds are 1,4-phenylenedimethylidyne,4,4-phenylenedimethylidyne, 2,5-xylenedimethylidyne,2,6-naphthylenedimethylidyne, 1,4-biphenylenedimethylidyne,1,4-p-terephenylenedimethylidyne, 9,10-anthracenediyldimethylidyne,4,4'-bis(2,2-di-t-butylphenylvinyl)biphenyl (hereinafter abbreviated as(DTBPVBi)), 4,4'-bis(2,2-diphenylvinyl)biphenyl (hereinafter abbreviatedas (DPVBi), and derivatives of these.

Also, the compounds represented by the general formula (R_(s) --Q)₂--AL--O--L, which are described in Japanese Patent Application Laid-openNo. 258862/1993 can be used, wherein L represents a hydrocarbon having6-24 carbon atoms and including a phenyl group, O-L represents aphenolate ligand, Q represents a substituted 8-quinolinolate ligand, Rsrepresents an 8-quinolinolate ring substitutional group selected tostereo-chemically prevent three or more substituted 8-quinolinolateligands from binding with an aluminum atom.

Given as specific examples of such compounds arebis(2-methyl-8-quinolinolate)(para-phenylphenolate) aluminum (III)(hereinafter abbreviated as (PC-7)) andbis(2-methyl-8-quinolinolate)(1-naphtholate) aluminum (III) (hereinafterabbreviated as (PC-17)).

In addition, Japanese Patent Application Laid-open No. 9953/1994discloses a method for producing mixed emitted light of a blue color anda green color by doping in an efficient manner. When using this methodfor forming the emitting layer of the present invention, theabove-mentioned emitting material is used as a host. As a dopant, astrongly fluorescent coloring material of a blue color to a green color,for example, a coumarin type or fluorescent coloring material similar tothose used in the above method can be given. Specifically, as the host,fluorescent materials mainly composed of distyryl arylene, preferably,for example, DPVBi can be given. As the dopant, diphenylaminostyrylarylene, preferably, for example,1,4-bis{4-N,N'-diphenylamino}styryl}benzene (DPAVB) can be given.

As the methods for forming an emitting layer using the above materials,known methods, for example, a vapor deposition method, a spin-coatingmethod, a LB method, or the like can be applied. A preferred emittinglayer is especially a molecularlysedimentary film. The molecularlysedimentary film is a film formed by deposition of a subject compound ina vapor phase or a film formed by solidifying a subject compound in asolution or in a liquid phase. The molecularly sedimentary film isgenerally distinguished from a thin film (molecularly cumulative film)formed in the LB method by differences in a coagulating structure and ahigh-order structure, or by a functional difference caused by thosestructures.

Also, the emitting layer can be formed in a similar manner by a methoddisclosed in Japanese Patent Application Laid-open No. 51781/1982 inwhich a binding agent such as a resin and a subject compound aredissolved in a solvent to make a solution and then a thin film is formedfrom the solution using a spin-coating method or the like.

The thickness of the emitting layer is preferably in a range from 5 nmto 5 μm, though there are no limitations to the thickness of theemitting layer produced in such a manner and the thickness of theemitting layer is optionally selected.

The emitting layer of the organic EL device has also the followingfunctions.

(1) Injection functions which allow positive holes to be injected froman anode or a positive hole injecting layer in the presence of anelectric field and allow electrons to be injected from a cathode or anelectron injecting layer.

(2) Transferring functions which allow the injected charges (electronsand positive holes) to be transferred by electric field force.

(3) Emitting functions which allows electrons and positive holes to becombined to emit light.

Incidentally, there may be a difference in ease between the injecting ofelectrons and the injecting of positive holes. Also, there maybeadifference between the transferability of positive holes and that ofelectrons in terms of mobility. However, it is desirable to transfereither positive holes or electrons.

(c) Positive hole injecting layer

Any material optionally selected from photo-conductive materialsconventionally used as a material for transferring a charge of positiveholes and from known materials used for a positive hole injecting layerof an organic EL device can be used as the material for the positivehole injecting layer provided as required. The material for the positivehole injecting layer which has a function either as a positive holeinjecting layer or as a barrier for an electron may be either an organicor inorganic compound.

Given as examples of these conventional materials are triazolederivatives (see the specification of U.S. Pat. No. 3,112,197, etc.),oxadiazole derivatives (see the specification of U.S. Pat. No.3,189,447, etc.), imidazole derivatives (Japanese Patent Publication No.16096/1962, etc.), polyarylalkane derivatives (see the specifications ofU.S. Pat. No. 3,615,402, U.S. Pat. No. 3,820,989, U.S. Pat. No.3,542,544, Japanese Patent Publications No. 555/1970 and No. 10983/1976,and Japanese patent Applications laid-open No. 93224/1976, No.17105/1980, No. 4148/1981, No. 108667/1980, No. 156953/1980, and No.36656/1981, etc.), pyrazoline derivatives and pyrazolone derivatives(see the specifications of U.S. Pat. No. 3,180,729, U.S. Pat. No.4,278,746, and Japanese Patent Applications Laid-open No. 88064/1980,No. 88065/1980, No. 105537/1974, No. 51086/1980, No. 80051/1981, No.88141/1981, No. 45545/1982, No. 112637/1979, and No. 74546/1980, etc.),phenylenediamine derivatives (see the specifications of U.S. Pat. No.3,615,404, Japanese Patent Publications No. 10105/1976, No. 3712/1971,and No. 25336/1972, Japanese Patent Applications Laid-open No.53435/1979, No. 110536/1979, and No. 119925/1979, etc.), arylaminederivatives (see the specifications of U.S. Pat. No. 3,567,450, U.S.Pat. No. 3,240,597, U.S. Pat. No. 3,658,520, U.S. Pat. No. 4,232,103,U.S. Pat. No. 4,175,961, U.S. Pat. No. 4,012,376, Japanese PatentPublications No. 35702/1974 and No. 27577/1964, Japanese PatentApplications Laid-open No. 144250/1980, No. 119132/1981, and No.22437/1981, and DRP No. 1,110,518, etc.), amino substituted chalconederivatives (see the specification of U.S. Pat. No. 3,526,501, etc.),oxazole derivatives (see the specification of U.S. Pat. No. 3,257,203,etc.), styrylanthracene derivatives (see the specification of JapanesePatent Application Laid-open No. 46234/1981, etc.), fluorenonederivatives (see the specification of Japanese Patent ApplicationLaid-open No. 110837/1979 and etc.), hydrazone derivatives (see thespecifications of U.S. Pat. No. 3,717,462, Japanese Patent ApplicationsLaid-open No. 59143/1979, No. 52063/1980, No. 52064/1980, No.46760/1980, No. 85495/1980, No. 11350/1982, No. 148749/1982, and No.311591/1990, etc.), stilbene derivatives (see the specifications ofJapanese Patent Applications Laid-open No. 210363/1986, No. 228451/1986,No. 14642/1986, No. 72255/1986, No. 47646/1987, No. 36674/1987, No.10652/1987, No. 30255/1987, No. 93445/1985, No. 94462/1985, No.174749/1985, and No. 175052/1985, etc.), silazane derivatives (see thespecification of U.S. Pat. No. 4,950,950, etc.), polysilane type (seethe specification of Japanese Patent Application Laid-open No.204996/1990, etc.), aniline type copolymers (see the specification ofJapanese Patent Application Laid-open No. 282263/1990, etc.), andelectro conductive macromolecular oligomers (especially a thiopheneoligomer) disclosed in Japanese Patent Application Laid-open No.211399/1989.

As the materials used for the positive hole injecting layer, the abovecompounds can be used. Among these, polphyrin compounds (disclosed inJapanese Patent Application Laid-open No. 2956965/1988) and aromatictertiary amines and styrylamine compounds (see the specifications U.S.Pat. No. 4,127,412, Japanese Patent Applications Laid-open No.27033/1978, No. 58445/1979, No. 149634/1979, No. 64299/1979, No.79450/1980, No. 144250/1980, No. 119132/1981, No. 295558/1986, No.98353/1986, and No. 295695/1988, etc.) are preferable. It is especiallypreferable to use the aromatic tertiary amines.

Typical examples of the above porphyrin compounds are porphin,1,10,15,20-tetraphenyl-21H, 23H-porphin copper (II),1,10,15,20-tetraphenyl-21H, 23H-porphin zinc (II),5,10,15,20-tetrakis(pentafluorophenyl)-21H, 23H-porphin, siliconphthalocyanine oxide, aluminum phthalocyanine chloride, phthalocyanine(non-metal), dilithium phthalocyanine, copper tetramethylphthalocyanine,copper phthalocyanine, chromium phthalocyanine, zinc phthalocyanine,lead phthalocyanine, titanium phthalocyanine oxide, magnesiumphthalocyanine, copper octamethylphthalocyanine, and the like.

Typical examples of the above aromatic tertiary amine and styrylaminecompounds are N,N,N',N'-tetraphenyl-4,4'-diaminophenyl,N,N'-diphenyl-N,N'-bis-(3-methylphenyl)- 1,1'-biphenyl!-4,4'-diamine(hereinafter abbreviated as "TPD"), 2,2-bis(4-di-p-tolylaminophenyl)propane,1,1-bis(4-di-p-tolylaminophenyl)cyclohexane,N,N,N',N'-tetra-p-tolyl-4,4'-diaminophenyl,1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane,bis(4-dimethylamino-2-methylphenyl)phenylmethane,bis(4-di-p-tolylaminophenyl)phenylmethane,N,N'-diphenyl-N,N'-di(4-methoxyphenyl)-4,4'-diaminobiphenyl,N,N,N',N'-tetraphenyl-4,4'-diaminophenyl ether,4,4-bis(diphenylamino)quadriphenyl, N,N,N-tri(p-tolyl)amine,4-(di-p-tolylamino)-4'- 4(di-p-tolylamino)styryl!stilbene,4-N,N-diphenylamino-(2-diphenylvinyl)benzene,3-methoxy-4'-N,N-diphenylaminostylbenzene, N-phenylcarbazole, compoundshaving two condensed aromatic rings in a molecule, for example,4,4'-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (hereinafter abbreviatedas (NPD)) disclosed in U.S. Pat. No. 5,061,569, and compounds in whichthree triphenylamine units are combined in a star-burst shape, forexample, 4,4',4"-tris N-(3-methylphenyl)-N-phenylamino!triphenylamine(hereinafter abbreviated as (MTDATA)) disclosed in Japanese PatentApplication Laid-open No. 308688/1992, and the like.

Also, other than the above-mentioned aromatic dimethylidine compoundsshown as the material for the emitting layer, inorganic compounds suchas p type Si and p type SiC can be utilized as the material used for thepositive hole injecting layer.

The positive hole injecting layer can be produced by forming a thin filmof the above-mentioned compound using a conventional method such as avacuum deposition method, spin-coating method, casting method, LBmethod, or the like. There are no restrictions as to the thickness ofthe positive hole injecting layer. However, the thickness of thepositive hole injecting layer is generally from 5 nm to 5 μm. Thispositive hole injecting layer may be structured of one layer made fromone or more of the above materials or may be a layer in which otherpositive hole injecting layers made from compounds differing from thecompound of that layer are laminated on that layer.

(d) Electron injecting layer

The electron injecting layer provided as required may have the functionof transferring, to the emitting layer, the electrons injected from thecathode. Optionalcompounds selected from conventionally known compoundsmay be used.

Typical examples of these compounds include nitro-substituted fluorenederivatives; anthraquinodimethane derivatives disclosed in JapanesePatent Applications Laid-open No. 149259/1982, No. 55450/1983, and No.104061/1988; diphenylquinone derivatives, thiopyrane dioxidederivatives, heterocyclic tetracarboxylic acid anhydrides such asnaphthaleneperillene and the like, and carbodiimides which are alldisclosed in Polymer Preprints, Japan Vol. 37. No. 3 (1988) p. 681 andthe like; fluorenylidenemethane derivatives disclosed in JapaneseJournal of Applied Physics, 27, L269 (1988), Japanese PatentApplications Laid-open No. 696657/1985, No. 143764/1986, and No.148159/1986; anthraquinonedimethane and anthrone derivatives disclosedin Japanese Patent Applications Laid-open No. 225151/1986 and No.233750/1986; oxadiazole derivatives disclosed by the above-describedHamada et al. at the conference of Appl. Phys; and a series of anelectron transfer compounds disclosed in Japanese Patent ApplicationLaid-open No. 194393/1984. Incidentally, though the above electrontransfer compounds are disclosed as the materials used for the emittinglayer in Japanese Patent Application Laid-open No. 194393/1984, it isconfirmed as a result of the studies of the present inventors that thesecompounds can be used as the materials for the electron injecting layer.

Also, thiazole derivatives produced by replacing an oxygen atom of theabove oxadiazole ring with a sulfur atom and quinoxaline derivativeshaving a quinoxaline ring known as an electron attracting group aregiven as examples of the materials for the electron injecting layer.Further, included as examples of the materials for the electroninjecting layer are metal complexes of 8-quinolinole, specifically,tris(8-quinolinole) aluminum (hereinafter abbreviated as "Alq"),tris(5,7-dibromo-8-quinolinole) aluminum, tris(2-methyl-8-quinolinole)aluminum, tris(5-methyl-8-quinolinole) aluminum, bis(8-quinolinole) zinc(hereinafter abbreviated as "Znq"), and metal complexes produced byreplacing the primary metals of these metal complexes with In, Mg, Cu,Ca, Sn, Ga, or Pb.

Other than the above, metal-free or metal phthalocyanine compounds of8-quinolinole derivatives or compounds produced by replacing theterminal group of these compounds with an alkyl group, sulphonic acidgroup, or the like. Also, the distyryl pyrazine derivatives can be usedas the materials for the electron injecting layer. Similar to thepositive hole injecting layer, inorganic semiconductors such asn-type-Si, n-type-SiC, or the like may be used.

The electron injecting layer can be produced by forming a thin film ofthe above-mentioned compound using a conventional method such as avacuum deposition method, spin-coating method, casting method, LBmethod, or the like. There are no restrictions as to the thickness ofthe electron injecting layer. However, the thickness of the electroninjecting layer is generally from 5 nm to 5 μm. This electron injectinglayer may be structured of one layer made from one or more of the abovematerials or may be a layer in which other electron injecting layersmade from compounds differing from the compound of that layer arelaminated on that layer.

(e) Cathode

As examples of the cathode, those using, as an electrode material,metals (these are called "electron injecting metal"), alloys, electroconductive compounds, and mixtures of these which have a low workfunction (less than 4 eV) are used. Given as examples of such anelectrode material are metals such as sodium, sodium/potassium alloy,magnesium, lithium, magnesium/copper mixtures, magnesium/silvermixtures, magnesium/aluminum mixtures, magnesium/indium mixtures,aluminum/aluminum oxide (Al₂ O₃), indium, lithium/aluminum mixtures, andrare earth metals, and the like. Among these, preferred examples aremixtures of the electron injecting metal and a secondary metal which hasa high work function and is stable in consideration of electroninjecting capability and durability to oxidation as an electrode.Specifically, magnesium/silver mixtures, magnesium/aluminum mixtures,magnesium/indium mixtures, aluminum/aluminum oxide (Al₂ O₃), andlithium/aluminum mixtures are given as the preferred examples.

A thin film of each of these electrode materials is formed by means ofvapor deposition, sputtering, or the like to produce the cathode.

If the light emitting from the emitting layer is taken out of thecathode in this manner, it is desirable that the transmittance by thecathode of the emitted light be more than 10%. In this case, the cathodecorresponds to the transparent electrode.

Here, the sheet resistance of the cathode is preferably less thanseveral hundreds Ω/□. The thickness of the cathode is usually from 10 nmto 1 μm, preferably from 50 nm to 200 nm.

In the multi-color light emission apparatus using an organic EL deviceas a emitting member, for example, one electrode pattern lineperpendicular to another pattern line is usually formed. When formingthe electrode on a thin film of an organic compound layer such as anemitting layer or the like using a photolithography method including wetetching, an organic compound layer is caused to greatly deteriorate sothat the photography method cannot be used in a stable manner.Therefore, the electrode pattern is formed through a mask having adesired shape when the electrode (anode or cathode) materials aretreated by vapor deposition or sputtering. When the electrode is notformed on a thin film of the organic compound layer for example on theglass plate, the pattern of the electrode pattern may be formed byphotolithography.

(f) Manufacture of organic EL device (example)

Using the above exemplified materials and methods, anode (for example,transparent electrode), an emitting layer, positive hole injecting layeras required, and electron injecting layer as required are formed andfurther a cathode (for example, electrode) is formed in that order tomanufacture an organic EL device. Also, an organic EL device can bemanufactured in the reverse order.

A manufacturing example of an organic EL device having a structure inwhich an anode, a positive hole injecting layer, a emitting layer, anelectron injecting layer, and a cathode are provided in that order on asupport substrate is illustrated below.

First, a thin film of a thickness of less than 1 μm, preferably from 10to 200 nm is formed of an anode material by vapor deposition,sputtering, or the like to form an anode. Next, a positive holeinjecting layer is formed on the anode. Formation of the positive holeinjecting layer can be carried out, as mentioned above, by means ofvacuum deposition, spin-coating, casting, LB, or the like. Among thesemeans, vacuum deposition is preferable to form a homogeneous film withease and to prevent occurrence of pin holes. When forming the positivehole injecting layer by means of vacuum deposition, the depositingconditions differ depending on the sort of compound (material for thepositive hole injecting layer) to be used, the crystalline structure andthe recombination structure of the object positive hole injecting layer,and the like. However, it is generally preferable to appropriatelyselect the depositing conditions from a depositing source temperatureranging from 50 to 450° C., a vacuum ranging from 10⁻⁷ to 10⁻³ torr, adepositing speed ranging from 0.01 to 50 nm/sec, a substrate temperatureranging from -50 to 300° C., and a film thickness ranging from 5 nm to 5μm.

Next, an emitting layer is formed on the positive hole injecting layerusing a desired organic emitting material. Formation of the emittinglayer can be carried out by providing a thin film of the organicemitting material by means of vacuum deposition, sputtering,spin-coating, and casting. Among these means, vacuum deposition ispreferable to form a homogeneous film with ease and to preventoccurrence of pin holes. When forming the emitting layer by means ofvacuum deposition, the depositing conditions differ depending on thesort of compound to be used. Generally, the depositing conditions can beselected from almost the same condition ranges as in the formation ofthe positive hole injecting layer.

Next, an electron injecting layer is formed on the emitting layer. It ispreferable to form the electron injecting layer by vacuum deposition toproduce a homogeneous film in the same way as in the formation of thepositive hole injecting layer or the emitting layer. The depositingconditions can be selected from almost the same condition ranges as inthe formation of the positive hole injecting layer or the emittinglayer.

Finally, a cathode is laminated on the electron injecting layer toproduce an organic EL element.

The cathode is formed of a metal so that vapor deposition or sputteringcan be used. However, vacuum deposition is preferably used to protectthe backing organic material from damage in forming a film.

When the organic EL device are produced in the above-mentionedprocesses, it is preferable that the steps from the step of forming theanode to the step of forming the cathode are thoroughly processed in oneevacuating operation.

Incidentally, in the case where a d.c. voltage is applied to the organicEL device, when applying 5-40 volts, allowing the anode and the cathodeto be provided with the positive (+) polarity and the negative (-)polarity respectively, luminance can be detected. When both the anodeand the cathode are inversely polarized, current never flows andluminance is not detected. Further, if an a.c. voltage is applied,luminance can be detected only at the time when the anode and thecathode are respectively polarized to the (+) polarity and the (-)polarity. The wave form of the a.c. current to be applied is optional.

2. Support Substrate

Materials which are not composed of an organic compound are preferableas the materials for the support substrate used in the presentinvention. Transparency is not required for the materials of the supportsubstrate. Materials which are shielded from light are rather preferableto output light from the fluorescent layer. It is desirable that atleast the surface of the support substrate facing the organic EL devicebe composed of an insulating material. There are no limitations to thethickness of the support substrate to the extent that it can reinforce athin transparent glass plate to be laminated subsequently without camberand distortion.

Typically, for example, a ceramic plate, metal plates which areprocessed by insulating treatment using inorganic oxides such as silica,alumina, or the like can be used as the materials for the supportsubstrate. In the case of using transparent materials such as glassplates (soda lime glass, heat resistance glass, and the like), quartzglass plates, or the like, the surface opposite to the organic EL devicemay be provided with a light-shielding film, reflecting plate with ablack film, or the like.

3. Fluorescent Layer

The fluorescent layer used in the present invention is composed of, forexample, a fluorescent coloring material and a resin or of anindependent fluorescent coloring material. The fluorescent layercomposed of the fluorescent coloring material and the resin are, forexample, a solid type produced by dissolving or dispersing thefluorescent coloring material in the binder resin.

Specific examples of types of coloring material will be explained. Firstgiven as examples of the coloring material converting ultraviolet orviolet emission of the organic EL device to blue emission are stilbenetype coloring materials such as 1,4-bis(2-methyl styryl) benzene(hereinafter abbreviated as (Bis-MSB)) and trans-4,4'-diphenyl stilbene(hereinafter abbreviated as (DPS)) and coumarin type coloring materialssuch as 7-hydroxy-4-methyl coumarin (hereinafter abbreviated as(coumarin 4)).

Given as examples of the coloring material converting blue or blue-greenemission of the organic EL device to green emission are a coumarin typecoloring material such as 2,3,5,6-1H,4H-tetrahydro-8-trifluoromethylquinolizino(9,9a,1-gh)coumarin(hereinafter abbreviated as (coumarin 153)),3-(2'-benzothiazolyl)-7-diethylaminocoumarin (hereinafter abbreviated as(coumarin 6)), and 3-(2'-benzimidazolyl)-7-N,N'-diethylaminocoumarin(hereinafter abbreviated as (coumarin 7)), other coumarin coloringmaterial type dyes such as basic yellow 51, and naphthalimide typecoloring materials such as solvent yellow 11 and solvent yellow 116.

Given as examples of the coloring material converting blue-greenemission of the organic EL device to orange-red emission are cyaninetype coloring materials such as4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4-H-pyran(hereinafter abbreviated as (DCM)), pyridine type coloring materialssuch as1-ethyl-2-(4-(p-dimethylaminophenyl)-1,3-butadienyl)-pyridinium-perchlorate(hereinafter abbreviated as (pyridine 1)), rhodamine type coloringmaterials such as rhodamine B and rhodamine 6G, and oxazine typecoloring materials.

Further, various dyes (direct dye, acidic dye, basic dye, disperse dye)can be used provided that they exhibit fluorescence. Also, pigmentalmaterials in which the above fluorescent coloring material is kneaded inadvance in a pigmental resin such as polymethacrylate ester, polyvinylchloride, vinyl chloride-vinyl acetate copolymer, alkyd resin, aromaticsulphonamide resin, urea resin, melamine resin, benzoguanamine resin, orthe like may be used.

In addition, these types of fluorescent coloring materials and pigmentsmay be, as required, used either independently or in combination. Theconversion rate of the fluorescent coloring material to red color islow. By mixing the above pigments, the rate of conversion from lightemission to fluorescent emission can be increased.

On the other hand, as the binder resin, transparent materials(transmittance of visible rays: more than 50%) are preferable. Given asexamples of such transparent materials are transparent resins (polymer)such as polymethyl methacrylate, polyacrylate, polycarbonate, polyvinylalcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, andcarboxymethyl cellulose.

Incidentally, photosensitive resins which can be used inphotolithography are also selected to separately dispose the fluorescentlayers on the same plane. For example, photocurable resists having areactive vinyl group such as an acrylate type, methacrylate type, vinylpolycinnamate type, and cyclic rubber type are given as examples of thephotosensitive resins. When using a printing method, printing inks(medium) using a transparent resin are selected. Given as examples ofthese transparent resins are a polyvinyl chloride resin, melamine resin,phenol resin, alkyd resin, epoxy resin, polyurethane resin, polyesterresin, maleic acid resin, monomers, oligomers, and polymers of apolyamide resin, polymethylmethacrylate, polyacrylate, polycarbonate,polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, andcarboxymethyl cellulose.

The fluorescent layers are commonly manufactured by the followingprocesses. The fluorescent layers mainly composed of fluorescentcoloring materials are manufactured by forming a film using a vacuumdeposition method or a sputtering method through a mask on which adesired pattern is formed for the fluorescent layers. On the other hand,the fluorescent layers composed of fluorescent coloring materials and aresin are manufactured by mixing fluorescent coloring materials, aresin, and a resist, dispersing or solubilizing to allow the mixture tobe liquefied, forming a film using a spin-coating method, roll-coatingmethod, or casting method, and patterning with a desired pattern for thefluorescent layers using a photolithographic method or a screen printingmethod.

There are no limitations to the thickness of the fluorescent layers tothe extent that the emission of the organic EL elements is sufficientlyabsorbed and the function of emitting fluorescent light is not impaired.The thickness of the fluorescent layers is in a range of from 10 nm to 1mm approximately.

For the fluorescent layer composed, especially, of fluorescent coloringmaterials and a binder resin, the concentration of the fluorescentcoloring material may be in such a range as that the emission of theorganic EL device can be absorbed efficiently without concentrationquenching of fluorescence. The concentration of the fluorescent coloringmaterial is in a range of from 1 to 10⁺⁴ mol/kg approximately to thebinder resin to be used, though this depends on the type of thefluorescent coloring material.

In addition, because the fluorescence conversion efficiency, especially,to a red color is low, fluorescent layers of a green color and a redcolor may be laminated to improve the efficiency.

4. Transparent Inorganic Oxide Substrate

As examples of the transparent inorganic oxide substrate used in thepresent invention, a substrate composed of a transparent andelectrically insulating inorganic oxide layer as shown in the secondinvention is given. However, the substrate is not necessarily formed ofan electrically insulating material.

Such an inorganic oxide substrate has a high efficiency in shielding,especially, aqueous vapor, oxygen, organic compound gas, and the like.

It is desirable that the plate thickness be as small as possible toimprove the characteristics in the angle of view, when the fluorescentlayers which absorb the light emission from the organic EL device andemit different fluorescent emission are separately disposed on the sameplane to emit multi-color light such as the three primary colors (RGB).

Usually, inorganic oxide substrates with a thickness of from 700 μm to1.1 mm are often used for a liquid crystal. However, in the presentcase, an inorganic oxide substrate with a thickness of from 1 μm to 700μm, and preferably from 1 μm to 200 μm is used.

If the thickness of the inorganic oxide substrate is not greater than 1μm, it is difficult to handle the inorganic oxide substrate which tendsto be broken. Also, when such inorganic oxide substrate is applied tothe support substrate on which the organic EL devices are laminated,using a sealing means, the inorganic oxide substrate is bent, showingremarkable camber or distortion. On the other hand, if the thicknessexceeds 200 μm, there is the case where the light emitted from theorganic EL device leaks from gaps between the inorganic oxide substrateand the fluorescent layer, which causes a narrow angle of view formulti-color light emission, thereby reducing practicability, though thisdepends on the fineness of the fluorescent layer.

5. Sealing Means

There are no limitations as to the sealing means used in the presentinvention. Materials, for example, composed of an ordinary adhesive maybe used as the sealing means.

Specifically, given as examples of the adhesive are photocurable orheatcurable adhesives having a reactive vinyl group of an acrylate typeoligomer and methacrylate type oligomer; and moisture-curable adhesivessuch as 2-cyanoacrylate and the like. In addition, heat and chemicalcurable type adhesives (two-liquid mixing type) can be used. Also,hotmelt type polyamide, polyester, and polyolefin are given as examplesof the adhesive. Adhesives capable of adhering and curing at from roomtemperature to 80° C. are preferable because there is the case where theorganic EL device deteriorates from heat treatment.

Application of the adhesive to a sealing portion may be carried outusing a dispenser or by printing such as screen printing.

There is no problem in curing after the application in the case of usingvisible light. However, there is the case where the organic EL devicedeteriorates when UV light is used and hence a method in which theorganic EL device is never irradiated with UV light such as by maskingor the like is effective.

6. Gap

In the present invention, the gap provided between the transparentinorganic oxide substrate and the organic EL device is used to absorbimpact or stress on the organic EL device. If a material used for asealing means is directly applied to the organic EL device, the organicEL device tends to be broken by the stress produced when the material iscured.

It is desirable that inert gas such as nitrogen, argon, or the like, oran inactive liquid such as hydrocarbon fluoride or the like be sealedinto the gap, because the organic EL device are liable to be oxidized byair if only air is present in the gap.

If the width of the gap is large in the case of using very finemulti-color light emission, light leakage increases and hence the angleof view is greatly reduced. Therefore, the width of the gap should bepreferably small, specifically from several μm to 200 μm in general,though this depends on the fineness of the multi-color light emission.

7. Protective Layer of the Fluorescent Layers (transparent flat film)

A protective layer of the fluorescent layers (transparent flat film)used as required in the present invention is used so that thefluorescent layer and color filter (including a black matrix) located atthe outside of the multi-color light emission apparatus are protectedfrom physical damage and deterioration from externally environmentalfactors such as water, oxygen, light, and the like. The protective layeris preferably composed of a transparent material with a visible lighttransmittance of 50% or more.

Specifically, as examples of the material for the protective layer,compounds having a reactive vinyl group of an acrylate type ormethacrylate type such as a photocurable resin and/or heat-curable resincan be given.

Also, given as examples of the material for the protective layer aretransparent materials such as a melamine resin, phenol resin, alkydresin, epoxy resin, polyurethane resin, polyester resin, maleic acidresin, monomer, polymer, or oligomer of a polyamide resin, polymethylmethacrylate, polyacrylate, polycarbonate, polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, and the like.

A UV ray absorber may be added to the protective layer to improve thelight resistance of the fluorescent layer.

The protective layer is prepared by forming a film of the above materialby spin-coating, roll coating, casting, or the like when the material isliquid. If the material is a photocurable resin, the film is irradiatedwith UV rays and is heat-cured as required, whereas if the material is aheat-curable resin, the film is heat-cured as is after the film isformed. On the other hand, when the material is shaped as a film, thematerial may be applied to the fluorescent layer using an adhesive.

There are no limitations as to the thickness of the protective layersince it has no influence on the angle of view. However, when thethickness is too great, it has some influence on the lighttransmittance, so that the thickness is preferably in a range from 1μmto 5 mm.

8. Transparent Substrate

Given as examples of the material used for a transparent substrate aretransparent glass substrates (ordinary visual light transmittance of 50%or more) including inorganic oxide substrates composed of such materialsas soda lime glass, heat resistance glass, quartz plate, and the like,and polymer substrates.

Because the thickness of the transparent substrate has no influence onthe angle of view, there are no limitations as to the thickness.However, when the thickness is too great, it has some influence on thelight transmittance, so that the thickness is preferably in a range from1 μm to 5 mm.

This transparent substrate is used for protecting the fluorescent layer.The transparent substrate is also used for a support substrate in thestep of forming a film of the fluorescent layer. Specifically, theabove-mentioned inorganic oxide substrate is applied to the transparentsubstrate using an ordinary transparent adhesive used such for thesealing means, after the formation of the film of the fluorescent layer.The resulting substrate may be then combined with the support substrateon which the organic EL device is laminated to seal the organic ELdevice.

9. Color Filter and Black Matrix

A color filter and black matrix used as required in the presentinvention are formed, for example, by performing desired patterning ondesired positions of a material selected from known materials, byphotolithography or printing.

10. Action of the Present Invention

In the present invention, the fluorescent layer is disposed in theposition opposite to the organic EL device through the inorganic oxidesubstrate so that gaseous substances such as organic monomers, aqueousvapor, and the like which cause the device to deteriorate are cut by theinorganic substrate, whereby the life of the organic EL device and hencethe life of the multi-color light emission apparatus using the organicEL device can be improved.

Generally, fluorescent layers which each absorb light of one coloremitted from the organic EL device are separately disposed on the sameplane to obtain light emission of a plurality of colors such as RGBprimary colors or the like. The present invention uses the transparentinorganic oxide substrate which is disposed on the fluorescent layerfacing the organic EL device whereby the above-mentioned effects areexpected. Also, the plate thickness of the transparent inorganicsubstrate is in a range of from 1 μm to 200 μm in the present invention,whereby not only are the above-mentioned effects obtained, but also theabsorption of the light emitted from the organic EL device to afluorescent layer other than the desired fluorescent layer and lightleakage from the gap between the fluorescent layer and the organic ELdevice decrease and hence light of a desired color can be produced,ensuring improvement in the characteristics in the angle of view formulti-color light emission.

Here, the fluorescent layer is used instead of a color filter becausecompared with the case of using the color filter highly efficientmulti-color light emission can be expected as mentioned above.

When a fluorescent layer is disposed on the outside of a multi-colorlight emission apparatus, there are cases where the fluorescent layer isdamaged by handling and deteriorates from external environmental factorssuch as water, oxygen, light, and the like. In this invention, however,the protective layer of the fluorescent layers is disposed on thefluorescent layer, thereby protecting the fluorescent layer. Also, thetransparent substrate is used for protecting the fluorescent layer orfor a support substrate in the step of forming the fluorescent layer.

II. Multi-color Light Emission Apparatus (second invention) and Processfor Manufacturing Thereof (third invention)

The second invention of the present application, designated as apparatus20, has, specifically, a structure selected from the structures (1) to(4) describe below from the above points of view. These structures (1)to (4) are shown in FIGS. 9-12. Incidentally, a fluorescent layer mayconvert the light emitted from the organic EL device into light of awave length longer than that of the light emitted from the organic ELdevice. The converted color is not limited to the following red or greencolor.

(1) Transparent support substrate 11/fluorescent layer 3R for convertinginto red color (hereinafter called "red color conversion fluorescentlayer"), fluorescent layer 3G for converting into green color(hereinafter called "green color conversion fluorescentlayer")/transparent and electrically insulating inorganic oxide layer12/organic EL device 1 (transparent electrode 1a/organic compound layer1b/electrode 1c);

(2) Transparent support substrate 11/red color conversion fluorescentlayer 3R, green color conversion fluorescent layer 3G/adhesive layer13/transparent and electrically insulating inorganic oxide layer12/organic EL device 1 (transparent electrode 1a/organic compound layer1b/electrode 1c);

(3) Transparent support substrate 11/red color conversion fluorescentlayer 3R, green color conversion fluorescent layer 3G/protective layerof the fluorescent layers (transparent flat film) 7/adhesive layer13/transparent and electrically insulating inorganic oxide layer12/organic EL device 1 (transparent electrode 1a/organic compound layer1b/electrode 1c); and

(4) Transparent support substrate 11/red color conversion fluorescentlayer 3R, green color conversion fluorescent layer 3G/protective layerof the fluorescent layers (transparent flat film) 7/transparent andelectrically insulating inorganic oxide layer 12/organic EL device 1(transparent electrode 1a/organic compound layer 1b/electrode 1c).

A red color filter and a green color filter may be assembled between thered color conversion fluorescent layer 3R and the transparent substrate,and between the green color conversion fluorescent layer 3G and thetransparent substrate respectively, thereby adjusting colors of light ofa red color and of a green color to improve these color purities.

A blue color filter 14 may be disposed in parallel and between the redcolor conversion fluorescent layer 3R and the green color conversionfluorescent layer 3G, thereby adjusting the colors of light emitted fromthe organic EL device to improve the color purities.

Also, as shown in FIG. 13, a black matrix 9b may be disposed at least ina space between the fluorescent layers 3R and 3G, and/or the colorfilter 14 to cut leakage of light emitted from the organic EL device 1and thereby to improve the visibility of multi-color light emission.

Further, as shown in FIG. 14, the transparent and electricallyinsulating inorganic oxide layer 12 may be composed of two layers, anupper inorganic oxide layer and a lower inorganic oxide layer so thatelution of inorganic ions from the lower inorganic oxide layer (forexample, soda-lime glass) is restrained by the upper inorganic oxidelayer to protect the organic EL device from the eluted ions.

The thickness of the transparent and electrically insulating inorganicoxide layer 12 is defined in a range of from 0.01 μm to 200 μm. If thethickness of the transparent and electrically insulating inorganic oxidelayer is not larger than 0.01 μm, it is near that of a monolayer of aninorganic oxide particle and hence deteriorative gas generated fromorganic compounds of the lower fluorescent layer, protective layer, andthe like never cut.

On the other hand, if the thickness of the transparent and electricallyinsulating layer exceeds 200 μm, the light emitted from the organic ELdevice leaks from the gap between the inorganic oxide layer and thefluorescent layers 3R, 3G so that the angle of view for multi-colorlight emission narrows, leading to a reduction in practicability,although this depends on the fineness of the fluorescent layers 3R and3G.

The multi-color light emission apparatus of the second invention and theprocess of the third invention for manufacturing same in the presentapplication are now illustrated for every structural element in detail.Materials used for the structural elements are not limited to theessential materials illustrated in the following descriptions. Also,details common with those in the first invention are omitted as far aspossible to avoid redundancies.

1. Organic EL Device

The organic EL device of this invention is similar to that used in thefirst invention.

(a) Anode

Materials similar to those used in the first invention can be used asthe materials for the anode.

(b) Emitting layer

Materials similar to those used in the first invention can be used asthe materials for an emitting layer.

(c) Positive hole injecting layer

Materials to those used in the first invention can be used as thematerials for a positive hole injecting layer.

(d) Electron Injecting Layer

Materials similar to those used in the first invention can be used asthe materials for an electron injecting layer.

(e) Cathode

Materials similar to those used in the first invention can be used asthe materials for a cathode.

(f) Manufacture of Organic EL Device(example)

The organic EL device used in this invention can be manufactured in thesame manner as in the first invention.

2. Transparent Support Substrate

A transparent support substrate used in the present invention ispreferably a transparent material (visible light transmittance of 50% ormore) such as, for example, a glass plate, plastic plate (polycarbonate,acryl, or the like), plastic film (polyethylene terephthalate, polyethersulfide, or the like), quartz plate, or the like. There are nolimitations as to the thickness of the support substrate to the extentthat it can reinforce a thin transparent glass plate to be laminatedsubsequently without camber and distortion.

3. Fluorescent Layer

Materials similar to those used in the first invention can be used asthe materials for a fluorescent layer.

4. Transparent and Electrically Insulating Inorganic Oxide Layer

A transparent and electrically insulating inorganic oxide layer used inthe present invention can be formed by laminating it on the fluorescentlayer, or a protective layer of the fluorescent layers or transparentadhesive layer, such as described below, for example, by vapordeposition, sputtering, dipping, spin-coating, roll-coating, casting,anodic oxidation of metal film, or the like.

The transparent and electrically insulating inorganic oxide layer may beformed of either one layer or two layers. With the two layer structurecomposed of an upper inorganic oxide layer and a lower inorganic oxidelayer, elution of inorganic ions from the lower inorganic oxide layer(for example, soda-lime glass) is restrained by the upper inorganicoxide layer to protect the organic EL device from the eluted ions.

Examples of the materials used for the transparent and electricallyinsulating inorganic oxide layer include silicon oxide (SiO₂), aluminumoxide (Al₂ O₃), titanium oxide (TiO₂), yttrium oxide (Y₂ O₃), germaniumoxide (GeO₂), zinc oxide (ZnO), magnesium oxide (MgO), calcium oxide(CaO), boron oxide (B₂ O₃), strontium oxide (SrO), barium oxide (BaO),lead oxide (PbO), zirconium oxide (ZrO₃), sodium oxide (Na₂ O), lithiumoxide (Li₂ O), potassium oxide (K₂ O), and the like. Among these,silicon oxide, aluminum oxide, and titanium oxide are preferable, sincethe transparency of the layer (film) thereof is high and the filmformation temperature is comparatively low (250° C. or less), hence thefluorescent layer or the protective layer deteriorates little.

Also, as the transparent and electrically insulating inorganic oxidelayer, it is more preferable to use a glass plate or a glass plateproduct made by forming a film of one or more compounds selected from agroup consisting of silicon oxide, aluminum oxide, titanium oxide, andthe like on at least one of the surface or back face of a transparentand insulating glass plate. A low temperature (150° C. or less)operation allowing this glass plate or glass plate product to be appliedto the fluorescent layer or the protective layer can be performed sothat these layers never entirely deteriorate. Also, the glass plate canespecially cut out aqueous vapor, oxygen, deteriorating gases such asmonomer gas and the like in an efficient manner.

Compositions of the glass plate are exemplified in Tables 1 and 2. Amongthese, typical examples are sodalime glass, barium-strontiumcontaining-glass, lead glass, aluminosilicate glass, borosilicate glass,barium borosilicate glass, and the like. Here, the electricallyinsulating inorganic oxide layer may have a composition containingmainly an inorganic oxide and may contain a nitride (for example, Si₃N₄) or fluoride (for example, CaF₂) It is preferable that the thicknessof the electrically insulating inorganic oxide layer be from 0.01 μm to200 μm, though there are no limitations as to the thickness to theextent that it acts as an obstacle to the light emission of the organicEL device. The glass plate or the glass plate product made by forming afilm of one or more compounds selected from a group consisting ofsilicon oxide, aluminum oxide, titanium oxide, and the like on at leastone of the surface or back face of a transparent and insulating glassplate has preferably a thickness of from 1 μm to 200 μm in considerationof the accuracy and strength of a plate glass.

The reason that inorganic oxide compounds including the glass plate aredesired is specifically because electro conductive and transparentinorganic materials such as ITO (indium tin oxides), which are oftenused, can be adopted as a transparent electrode (anode) of the organicEL device and also because these have excellent mutual affinity andadhesion.

Here, aqueous vapor, oxygen, and gas from organic compounds such asmonomers and the like exhibit the problem of a reduction in the lightemission life of the organic EL device. Therefore, it is necessary forthe transparent and electrically insulating inorganic oxide layer topossess characteristics that do not cause generation of aqueous vapor,oxygen, and gases of organic compounds such as monomers and the like andwherein the external intrusion of these harmful compounds can beprevented.

Specifically, the water content of the inorganic oxide layer is measuredby thermal analysis (DTA (Differential Thermal Analysis) and DSC(Differential Scanning Calorimeter)). Also, the gas permeability of theinorganic oxide layer for aqueous vapor and for oxygen is measuredaccording to a test method for permeability of JIS K7126 and the like.If, especially, the water content is 0.1% by weight or less and the gaspermeability is 10⁻¹³ cccm/cm² scmHg or less, reduction in the lightemission life of the organic EL device, indicated by generation of darkspots can be prevented.

                  TABLE 1    ______________________________________    Glass composition type    ______________________________________    1)         R.sub.2 O--R'O--SiO.sub.2               Na.sub.2 O--CaO/MgO--SiO.sub.2 (soda-lime glass)               Na.sub.2 O/K.sub.2 O--BaO/SrO--SiO.sub.2               Na.sub.2 O/K.sub.2 O--CaO/ZnO--SiO.sub.2    2)         R.sub.2 O--PbO--SiO.sub.2               K.sub.2 O/Na.sub.2 O--PbO--SiO.sub.2 (lead glass)    3)         R.sub.2 O--B.sub.2 O.sub.3 --SiO.sub.2               Na.sub.2 O--B.sub.2 O.sub.3 --SiO.sub.2 (borosilicate glass)               K.sub.2 O--B.sub.2 O.sub.3 --SiO.sub.2    4)         R'O--B.sub.2 O.sub.3 --SiO.sub.2               PbO--B.sub.2 O.sub.3 --SiO.sub.2               PbO/ZnO--B.sub.2 O.sub.3 --SiO.sub.2               PbO--B.sub.2 O.sub.3 --SiO.sub.2 + filler               ZnO--B.sub.2 O.sub.3 --SiO.sub.2    5)         R'O--Al.sub.2 O.sub.3 --SiO.sub.2               CaO/MgO--Al.sub.2 O.sub.3 --SiO.sub.2 (aluminosilicate               glass)               MgO--Al.sub.2 O.sub.3 --SiO.sub.2               PbO/ZnO--Al.sub.2 O.sub.3 --SiO.sub.2    6)         R.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2               Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2               Na.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2    7)         R'O--TiO.sub.2 --SiO.sub.2               BaO--TiO.sub.2 --SiO.sub.2    8)         R.sub.2 O--ZrO.sub.2 --SiO.sub.2               Na.sub.2 O/Li.sub.2 O--ZrO.sub.2 --SiO.sub.2    9)         R'O--P.sub.2 O.sub.5 --SiO.sub.2               CaO--P.sub.2 O.sub.5 --SiO.sub.2    10)        R'O--SiO.sub.2               CaO/BaO/PbO--SiO.sub.2    11)        SiO.sub.2    12)        R.sub.2 O--R'O--B.sub.2 O.sub.3               Li.sub.2 O--BeO--B.sub.2 O.sub.3    13)        R'O--R".sub.2 O.sub.3 --B.sub.2 O.sub.3               CaO/BaO--Al.sub.2 O.sub.3 --B.sub.2 O.sub.3               CaO/PbO--Lu.sub.2 O.sub.3 --B.sub.2 O.sub.3    14)        R.sub.2 O--Al.sub.2 O.sub.3 --P.sub.2 O.sub.5               K.sub.2 O--Al.sub.2 O.sub.3 --P.sub.2 O.sub.5    15)        R'O--Al.sub.2 O.sub.3 --P.sub.2 O.sub.5               BaO/CaO--Al.sub.2 O.sub.3 --P.sub.2 O.sub.5               ZnO--Al.sub.2 O.sub.3 --P.sub.2 O.sub.5    ______________________________________     R: monovalent element,     R': bivalent element,     R": trivalent element

                  TABLE 2    ______________________________________                 Composition    Classification                 (shown as a unary system-ternary system    ______________________________________    1   Simple oxide SiO.sub.2, B.sub.2 O.sub.3, GeO.sub.2, As.sub.2 O.sub.3    2   Silicate     Li.sub.2 O--SiO.sub.2, Na.sub.2 O--SiO.sub.2, K.sub.2                     O--SiO.sub.2                     MgO--SiO.sub.2, CaO--SiO.sub.2, BaO--SiO.sub.2,                     PbO--SiO.sub.2                     Na.sub.2 O--CaO--SiO.sub.2                     Al.sub.2 O.sub.3 --SiO.sub.2    3   Borate       Li.sub.2 O--B.sub.2 O.sub.3, Na.sub.2 O--B.sub.2                     O.sub.3, K.sub.2 O--B.sub.2 O.sub.3                     MgO--B.sub.2 O.sub.3, CaO--B.sub.2 O.sub.3, PbO--B.sub.2                     O.sub.3                     Na.sub.2 O--CaO--B.sub.2 O.sub.3, ZnO--PbO--B.sub.2                     O.sub.3                     Al.sub.2 O.sub.3 --B.sub.2 O.sub.3, SiO.sub.2 --B.sub.2                     O.sub.3    4   Phosphate    Li.sub.2 O--P.sub.2 O.sub.5, Na.sub.2 O--P.sub.2                     O.sub.5                     MgO--P.sub.2 O.sub.5, CaO--P.sub.2 O.sub.5, BaO--P.sub.2                     O.sub.5                     K.sub.2 O--BaO--P.sub.2 O.sub.5                     Al.sub.2 O.sub.3 --P.sub.2 O.sub.5, SiO2--P.sub.2                     O.sub.5, B.sub.2 O.sub.3 --P.sub.2 O.sub.5                     V.sub.2 O.sub.5 --P.sub.2 O.sub.5, Fe.sub.2 O.sub.3                     --P.sub.2 O.sub.5, WO.sub.3 --P.sub.2 O.sub.5    5   Germanate glass                     Li.sub.2 O--GeO.sub.2, Na.sub.2 O--GeO.sub.2, K.sub.2                     O--GeO.sub.2                     B.sub.2 O.sub.3 --GeO.sub.2, SiO.sub.2 --GeO.sub.2    6   Tungstate    Na.sub.2 O--WO.sub.3, K.sub.2 O--WO.sub.3    7   Molybdate    Na.sub.2 O--MoO.sub.3, K.sub.2 O--MoO.sub.3, L.sub.2                     O--MoO.sub.3    8   Tellurate    Na.sub.2 O--TeO.sub.2    9   Borosilicate Na.sub.2 O--B.sub.2 O.sub.3 --SiO.sub.2    10  Aluminosilicate                     Na.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2, CaO--Al.sub.2                     O.sub.3 --SiO.sub.2    11  Aluminoborate                     CaO--Al.sub.2 O.sub.3 --B.sub.2 O.sub.3, ZnO--Al.sub.2                     O.sub.3 --B.sub.2 O.sub.3    12  Aluminoborosilicate                     Na.sub.2 O--Al.sub.2 O.sub.3 --B.sub.2 O.sub.3 --SiO.sub.                     2    13  Fluoride     BeF.sub.2, NaF--BeF.sub.2                     ZrF.sub.4 --BaF.sub.2 --ThF.sub.4, GdF.sub.3 --BaF.sub.2                     --ZrF.sub.4    14  Phosphorus fluoride                     Al(PO.sub.3).sub.3 --AlF.sub.3 --NaF--CaF.sub.2    15  Oxyhalogenide                     Ag.sub.2 O--AgI--P.sub.2 O.sub.5    16  Oxynitride   MgO--Al.sub.2 O.sub.3 --AlN--SiO.sub.2    ______________________________________

5. Protective Layer of the Fluorescent Layers (transparent flat film)

Materials similar to those of the first invention may be used as aprotective layer of the fluorescent layers (transparent flat film).

However, the thickness of the protective layer in the second inventionis preferably from 0.5 μm to 100 μm approximately. It is desirable thatthe thickness of the protective layer be as small as possible to reducelight leakage from the gap between the fluorescent layer and the organicEL device with respect to the light emitted from the organic EL device.However, if the film thickness is too small, no effect of protecting thefluorescent layer can be obtained, depending on the type of adhesive.

6. Transparent Adhesive Layer

It is desirable that a transparent adhesive layer, which is used asrequired in the present invention, be used in the case of adopting thesubstrate produced by forming the fluorescent layer (including a colorfilter, black matrix, and protective layer as required) on thetransparent support substrate and also, especially, in the case ofadopting a glass plate as the inorganic oxide layer. A material which istransparent (visible transmittance of 50% or more), at least in theportion where the light emitted from the organic EL device istransmitted is preferable as the material used for the transparentadhesive layer.

Specifically given as examples of the adhesive are photocurable orheat-curable adhesives having a reactive vinyl group of an acrylic acidtype oligomer and methacrylic acid type oligomer; and moisture-curableadhesives such as 2-cyanoacrylate and the like. Also, heat-curable andchemical-curable type (two liquid mixture type) adhesives such as anepoxy or the like can be used.

An adhesive having a low viscosity (about 100 cp or less) ensures thatthere is no formation of air bubbles when it is applied and henceuniform application is allowable. However, the low viscosity adhesivedissolves and erodes the fluorescent layer depending on the conditionsso that it is necessary to laminate the above protective layer on thefluorescent layer. An adhesive having a high viscosity (about 100 cp ormore) is scarcely dissolved, and erodes the fluorescent layer so thatthere is the case where the protective layer of the fluorescent layersis not required. On the contrary, this causes formation of air bubbles,hence uniform application can be achieved only with difficulty. Thenecessity of providing the protective layer of the fluorescent layersmay be determined according to the characteristics of the adhesive.

The adhesive is applied on a substrate, on which the fluorescent layer(including a color filter, black matrix, and protective layer asrequired) is formed to form a film by spin-coating, roll coating,casting, or the like. Then, a glass plate, on which the transparentelectrode has been formed or is to be formed, or a glass plate productmade by forming a film of one or more compounds selected from a groupconsisting of silicon oxide, aluminum oxide, titanium oxide, and thelike on at least one of the surface or back face of a transparent,insulating glass plate is applied to the substrate through the adhesivefilm by means of light (UV rays), heat (up to 150° C.), chemical mixing,or the like according to the specification of the adhesive.

It is preferable that the thickness of the adhesive layer be in theorder of 0.1 μm to 200 μm. It is desirable that the thickness of theprotective layer be as small as possible to reduce light leakage fromthe gap between the fluorescent layer and the organic EL device withrespect to the light emitted from the organic EL device, therebyimproving the characteristics of the angle of view . However, if thefilm thickness is too small, there is the case where uniform applicationcan be attained only with difficulty due to unevenness between thefluorescent layers.

7. Color Filter and Black Matrix

A color filter and a black matrix used as required in the presentinvention are formed, for example, by appropriately patterning desiredpositions of a material selected from known materials byphotolithography or printing.

8. Action of the Present Invention

In the present invention with the above structure, the inorganic oxidelayer with a thickness of from 0.01 to 200 μm cuts out aqueous vapor,oxygen, or gaseous substances such as organic monomers, which areconsidered to adhere to or to be contained originally in small amountsin organic compounds forming the lower fluorescent layer or theprotective layer of the fluorescent layers or which are considered to begenerated by the fluorescent layer or the protective layer by heat whenthe organic EL device emits light. Hence, the causes of deterioration ofthe organic EL device can be reduced. Especially in the case of using aglass plate as the inorganic oxide layer, such deteriorative gaseoussubstances can be prevented to a high degree, resulting in improvementin storage stability and in the light emission life of the multi-colorlight emission apparatus.

Also, the film thickness of the inorganic oxide layer is 200 μm or lessin the present invention, so that undesirable light emission caused byabsorption of the light emitted from the organic EL device by afluorescent layer other than the desired fluorescent layer and lightleakage from the gap between the fluorescent layer and the organic ELdevice decrease, hence light of a desired color could be produced,resulting in improvement in the characteristics of the angle of view formulti-color light emission.

Also, the inorganic oxide layer and the transparent electrode (usuallycomposed of ITO (indium or tin oxide) provide a higher quality adhesionthan those composed of organic compounds, thereby facilitating thepatterning (usually by photolithography) of the transparent electrode.

Also, in the present invention, the transparent adhesive layer is placedon the boundary of the inorganic oxide layer on the side of thefluorescent layer. Especially in the case where the inorganic oxidelayer located at the boundary of the transparent electrode of theorganic EL device on the side of the fluorescent layer is composed of aglass plate, adhesion between the organic EL device and the fluorescentlayer is enhanced and the organic EL device and the fluorescent layerare integrated. Further, when the transparent protective layer of thefluorescent layers is arranged between the adhesive layer and thefluorescent layer, the fluorescent layer is protected from beingdissolved and eroded by the adhesive layer. The protective layer ensuresthat the uneven film thickness of the fluorescent layers to beseparately disposed on the same plane is moderated, the deformation ofthe inorganic oxide layer on the fluorescent layer is reduced, anddefects such as cracking and the like in the inorganic oxide layer orthe transparent electrode decrease.

If a thin glass plate with a thickness of from 1 μm to 200 μm is used asthe inorganic oxide layer, it is difficult to form an organicelectroluminescent device directly on the glass plate in a stable mannersince the thin film-glass plate which is physically fragile tends to becambered and distorted. However, in the process of the presentinvention, this thin glass plate is combined with the transparentsupport substrate on which the fluorescent layer and the protectivelayer of the fluorescent layers are laminated via the adhesive layer.Also, the organic electroluminescence devices are laminated in order, sothat the multi-color light emission apparatus can be produced in astable manner.

EXAMPLES

The present invention will be explained in more detail by way ofexamples, which are not intended to be limiting of the presentinvention.

Example 1

An methacrylate type resist containing carbon black (CK 2000,manufactured by Fuji Hunt Electronics Technology Co., Ltd.) was appliedby spin-coating to one the faces of a support substrate (Glass 7059,manufactured by Corning Co., Ltd.) with dimensions of 25 mm×75 mm×1.1 mm(thickness), which was baked at 200° C. to form a black film (about 2 μmthickness).

Next, the face opposite to the black film of this substrate was washedwith IPA and further irradiated with UV light. Then, the substrate wassecured to a substrate holder of a vapor deposition unit (manufacturedby ULVAC Corporation). As materials for vapor deposition, MTDATA and NPDfor a positive hole injecting layer, DPVBi for an emitting material, andAlq for an electron injecting layer were placed in a resistance heatingmolybdenum boat. Ag was attached to a tungsten filament as a secondmetal for an electrode (cathode), and Mg was attached to the molybdenumboat as an electron injecting metal for an electrode (cathode).

After that, the pressure in a vacuum vessel was reduced to 5×10⁻⁷ torrand then the above materials were sequentially laminated in thefollowing order through a mask which enabled film to be formed in arange of 10 mm×60 mm. A vacuum was maintained during the steps between astep of forming electrodes and a step of forming the positive holeinjecting layer by one evacuating operation.

First, Mg and Ag were vapor-deposited as the electrode simultaneously atvapor deposition rates of 1.3-1.4 nm/s and 0.1 nm/s respectively to afilm thickness of 200 nm. Then, an electron injecting layer was formedby depositing Alq at a vapor deposition rate of 0.1-0.3 nm/s to a filmthickness of 20 nm. Next, an emitting layer was formed by depositingDPVBi at a vapor deposition rate of 0.1-0.3 nm/s to a film thickness of50 nm. Finally, a positive hole injecting layer was formed by depositingNPD at a vapor deposition rate of 0.1-0.3 nm/s to a film thickness of 20nm and also depositing MTDATA at a vapor deposition rate of 0.1-0.3 nm/sto a film thickness of 200 nm.

Next, the substrate was transferred to a sputtering apparatus. Atransparent electrode (anode) film of ITO (indium oxide or tin oxide)with a thickness of 120 nm and a surface resistance of 20 Ω/□ was formedon this substrate at room temperature through a mask which enabled afilm to be formed of an area of 10 mm×60 mm to create an organic ELdevice. Here, the mask was lifted so that the ranges of the electrodesand transparent electrode were crossed (in a range of 10 mm×55 mm) andthe terminal of each electrode could be taken.

Next, an epoxy, two-liquid mixing type adhesive (Araldite, manufacturedby Ciba Geigy Co., Ltd.) was applied to the peripheries of the crossedportions (10 mm×55 mm) at a width of 1 mm approximately with partialslits using a dispenser to form a substrate A.

Then, a transparent inorganic oxide substrate (barium borosilicateglass) (substrate B) of 25 mm×75 mm×1.1 mm (thickness) was applied tothe substrate A and the adhesive was cured. After that, hydrocarbonfluoride (Fluorinert, manufactured by Sumitomo 3M Corp.) was injectedunder a nitrogen atmosphere, using an injection needle, through theabove slits into gaps between the support substrate (substrate A.) andthe applied substrate (substrate B). Then, the same adhesive was filledinto the slits in the cured adhesive and cured.

Next, characters EL with a width of 1 mm were printed on the substratewithin the portion corresponding to the crossed portion (a range of 10mm×55 mm) through a screen board using an ink (viscosity 8,000 cp)produced by dissolving coumarin 6/polyvinyl chloride resin (molecularweight of 20,000) in cyclohexanone in the coumarin 6 concentration of0.03 mol/kg (film). The characters were air-dried to prepare afluorescent pattern of the characters EL (15 μm thickness).

A multi-color light emission apparatus composed of the organic EL devicewas manufactured in this manner as shown in FIG. 1. When a d.c. voltageof 8 V was applied between the transparent electrode (anode) and theelectrode (cathode) of the multi-color light emission apparatus, thecrossed portions of the transparent electrodes (anodes) and theelectrodes (cathodes) emitted light. The luminance of the light viewedfrom the portion lacking the fluorescent layer was 100 cd/m². The CIEchromaticity coordinates (JIS Z 8701) were as follows: x=0.15, y=0.15.Light of a blue color was detected.

Also, the luminance of the light viewed from the fluorescent layerprovided with the patterned characters EL was 120 cd/m² and the CIEchromaticity coordinates were as follows: x=0.28, y=0.62. Light of ayellowish green color was detected.

The multi-color light emission apparatus was allowed to stand in theatmosphere for two weeks. As a result, the multi-color light emissionapparatus maintained uniform light emission without changes in luminanceand chromaticity and also without dark spots appearing as deteriorationof the device progressed.

Example 2

A support substrate (substrate A) provided with an organic EL device wascombined with a transparent inorganic oxide substrate (substrate B) inthe same manner as in Example 1 to form a substrate containing a gapfilled with hydrocarbon fluoride. Next, the characters EL with a widthof 1 mm were printed on the substrate within the portion correspondingto the crossed portion (range 10 mm×55 mm) of an electrode and atransparent electrode through a screen board using an ink (viscosity8,000 cp) produced by dissolving 43% (for film) by weight of a pigmentcontaining rhodamine/polyvinyl chloride resin (molecular weight 20,000)in cyclohexanone. The characters were air-dried to prepare a fluorescentpattern of the characters EL (20 μm thickness).

A multi-color light emission apparatus composed of the organic EL devicewas manufactured in this manner as shown in FIG. 1. When a d.c. voltageof 8 V was applied between the transparent electrode (anode) and theelectrode (cathode) of the multi-color light emission apparatus, thecrossed portions of the transparent electrodes and the electrodesemitted light. The luminance of the light viewed from the portionlacking the fluorescent layer was 100 cd/m². The CIE chromaticitycoordinate (JIS Z 8701) was as follows: x=0.15, y=0.15. Light of a bluecolor was detected.

Also, the luminance of the light viewed from the fluorescent layerprovided with the patterned characters EL was 30 cd/m² and the CIEchromaticity coordinates were as follows: x=0.60, y=0.31. Light of a redcolor was detected.

The multi-color light emission apparatus was allowed to stand in theatmosphere for two weeks. As a result, the multi-color light emissionapparatus maintained uniform light emission without changes in luminanceand chromaticity coordinate and also without dark spots appearing asdeterioration of the device progressed.

Example 3

An methacrylate type resist containing carbon black (CK 2000,manufactured by Fuji Hunt Electronics Technology Co., Ltd.) was appliedby spin-coating to one face of a support substrate (Glass 7059,manufactured by Corning Co., Ltd.) of 100 mm×100 mm×1.1 mm (thickness),which was baked at 200° C. to form a black film with a thickness ofabout 2 μm.

Next, the face opposite to the black film of this substrate was washedwith IPA and further irradiated with UV light. Then, the substrate wassecured to a substrate holder of a vapor deposition unit (manufacturedby ULVAC Corporation). As materials for vapor deposition, MTDATA and NPDfor a positive hole injecting layer, DPVBi for a emitting material, andAlq for an electron injecting layer were placed in a resistance heatingmolybdenum boat. Ag as a second metal for an electrode (cathode) wasattached to a tungsten filament, and Mg as an electron injecting metalfor an electrode (cathode) was attached to the molybdenum boat.

After that, the pressure in a vacuum vessel was reduced to 5×10⁻⁷ torr.First, a film with a pattern of an electrode was formed using a maskcapable of transferring a stripe pattern of an 1.5 mm pitch (1.4 mmlines and 0.1 mm gaps) in a range of 72 mm×72 mm. Next, films of layersfrom an electron injecting layer to a positive hole injecting layer wereformed using a mask enabling a film to be formed in a range of 72 mm×72mm. A vacuum was maintained during the steps between the step of formingthe electrodes and the step of forming the positive hole injecting layerby one evacuating operation.

First, Mg and Ag were simultaneously vapor-deposited as the electrodesat vapor deposition rates of 1.3-1.4 nm/s and 0.1 nm/s respectively to afilm thickness of 200 nm. Then, an electron injecting layer was formedby depositing Alq at a vapor deposition rate of 0.1-0.3 nm/s to a filmthickness of 20 nm. Next, an emitting layer was formed by depositingDPVBi at a vapor deposition rate of 0.1-0.3 nm/s to a film thickness of50 nm. Finally, a positive hole injecting layer was formed by depositingNPD at a vapor deposition rate of 0.1-0.3 nm/s to a film thickness of 20nm and also depositing MTDATA at a vapor deposition rate of 0.1-0.3 nm/sto a film thickness of 400 nm.

Next, the substrate was transferred to a sputtering apparatus. A film ofa transparent electrode (anode) of ITO with a thickness of 120 nm and asurface resistance of 20 Ω/□ was formed on this substrate at roomtemperature through a mask which enabled a solid film with a stripepattern of 4.5 mm pitch (4.0 mm lines, 1.0 mm gaps) to be formed in arange of 72 mm×72 mm, to form an organic EL device. Here, the mask waslocated so that the ranges of the electrodes and transparent electrodeswere crossed and the terminal of each electrode could be taken.

Next, an epoxy, two-liquid mixing type adhesive (Araldite, manufacturedby Ciba Geigy Co., Ltd.) was applied to the peripheries of the crossedportions (a range of 72 mm×72 mm) at a width of 1 mm approximately withpartial slits using a dispenser to form a substrate C.

Then, a transparent inorganic oxide substrate (barium borosilicateglass) (substrate D) of 100 mm×100 mm×0.15 mm was applied to thesubstrate C and the adhesive was cured. After that, hydrocarbon fluoride(Fluorinert, manufactured by Sumitomo 3M Corp.) was injected under anitrogen atmosphere, using an injection needle, through the above slitsinto a gap between the support substrate (substrate C) and the appliedsubstrate (substrate D). Then, the same adhesive was filled into theslits in the cured adhesive and cured.

Next, a pattern of a fluorescent layer A with a thickness of 15 μm wasprinted by screen printing on the substrate using an ink (viscosity8,000 cp) produced by dissolving coumarin 6/polyvinyl chloride resin(molecular weight 20,000) in cyclohexanone in the coumarin 6concentration of 0.03 mol/kg (film) through a screen board which enableda stripe pattern of 1.4 mm lines and 3.1 mm gaps to be formed afteraligning with the electrodes (cathodes) of the organic EL device,followed by air-drying.

Next, a pattern of a fluorescent layer B with a thickness of 20 μm wasprinted by screen printing on the substrate using an ink (viscosity8,000 cp) produced by dissolving 43% (for film) by weight of a pigmentcontaining rhodamine/polyvinyl chloride resin (molecular weight 20,000)in cyclohexanone through a screen board which enabled a stripe patternof 1.4 mm lines and 3.1 mm gaps to be formed after lifting the pattern1.5 mm from the pattern of the fluorescent layer A in a directionperpendicular to the stripe, followed by air-drying.

A multi-color light emission apparatus composed of the organic EL device(dot matrix type) was manufactured in this manner as shown in FIG. 4.When a d.c. voltage of 8 V was applied between the anode and the cathodeof the multi-color light emission apparatus, the crossed portions of thetransparent electrodes (anodes) and the electrodes (cathodes) emittedlight. The luminance of the light viewed from the portion lacking thefluorescent layer was 100 cd/m². The CIE chromaticity coordinate (JIS Z8701) was as follows: x=0.15, y=0.15. Light of a blue color wasdetected.

Also, the luminance of the light viewed from the fluorescent layer A was120 cd/m² and the CIE chromaticity coordinates were as follows: x=0.28,y=0.62. Light of a yellowish green color was detected.

On the other hand, the luminance of the light viewed from thefluorescent layer B was 30 cd/m² and the CIE chromaticity coordinateswere as follows: x=0.60, y=0.31. Light of a red color was detected.

The multi-color light emission apparatus was allowed to stand in theatmosphere for two weeks. As a result, the multi-color light emissionapparatus maintained uniform light emission without changes in luminanceand chromaticity coordinate and also without dark spots appearing asdeterioration of the device progressed. Also, the angle of view definedby the range in which leakage of light (mono-chromatic light) was notconfirmed was ±60° which was a practical level.

Example 4

A coating agent composed of an aqueous polyvinyl pyrrolidone (molecularweight 360,000) solution was applied by spin-coating on the fluorescentlayer of the multi-color light emission apparatus composed of theorganic EL device manufactured in Example 1 and air-dried to laminate aprotective layer of the fluorescent layers with a thickness of 10 μm.

A multi-color light emission apparatus composed of the organic EL devicewas manufactured in this manner as shown in FIG. 2. The multi-colorlight emission apparatus was allowed to stand in the atmosphere for twoweeks. As a result, the multi-color light emission apparatus maintaineduniform light emission without changes in luminance and chromaticitycoordinates and also without dark spots appearing as deterioration ofthe device progressed.

Also, because the protective layer was laminated, the fluorescent layerwas never damaged even if the fluorescent layer was contacted by a nailand the handling, such as carrying, of the apparatus was easy.

Example 5

An adhesive was applied to a substrate produced by forming an organic ELdevice on a support substrate in the same manner as in Example 3 to forma substrate X.

Separately, a pattern of a fluorescent layer A with a thickness of 15 μmwas printed by screen printing on a transparent substrate (7059,manufactured by Corning Co., Ltd.) of 100 mm×100 mm×0.70 mm (thickness)using an ink (viscosity 8,000 cp) produced by dissolving coumarin6/polyvinyl chloride resin (molecular weight 20,000) in cyclohexanone inthe coumarin 6 concentration of 0.03 mol/kg (film) through a screenboard which enabled a stripe pattern of 1.4 mm lines and 3.1 mm gaps tobe formed after aligning with the location corresponding to electrodesof the organic EL device, followed by baking at 120° C.

Next, a pattern of a fluorescent layer B with a thickness of 20 μm wasprinted by screen printing on the substrate using an ink (viscosity8,000 cp) produced by dissolving 43% (for film) by weight of a pigmentcontaining rhodamine/polyvinyl chloride resin (molecular weight 20,000)in cyclohexanone through a screen board which enabled a stripe patternof 1.4 mm lines and 3.1 mm gaps to be formed after lifting the pattern1.5 mm from the pattern of the fluorescent layer A in a directionperpendicular to the stripe, followed by baking at 120° C.

An aqueous polyvinyl pyrrolidone (molecular weight 360,000) solution wasapplied by spin-coating to the substrate to laminate a protective layerof the fluorescent layers with a thickness of 10 μm. Next,2-cyanoacrylate type adhesive (*Aron α, manufactured by ToagoseiChemical Industry Co., Ltd.) was applied to the entire substrate bycasting to provide an inorganic oxide substrate (aluminoborosilicateglass) of 100 mm×100 mm×0.05 mm (thickness) on the substrate to form asubstrate Y.

The substrate Y was applied to the above substrate X so that a 0.05 mmthickness substrate of the substrate Y faced the organic EL device andthe fluorescent layers A and B were aligned with the electrodes of theorganic EL device and the adhesive was cured. After that, hydrocarbonfluoride (Fluorinate, manufactured by Sumitomo 3M Corp.) was injectedunder a nitrogen atmosphere using an injection needle, through slits inthe cured adhesive into a gap between the support substrate (substrateX) and the applied substrate (substrate Y). Then, the same adhesive wasfilled into the slits in the cured adhesive and cured.

The luminance and chromaticity coordinate of the light emitted in themulti-color light emission apparatus, composed of the organic EL deviceshown in FIG. 6 and designated as apparatus 10, which was manufacturedin this manner, were the same as those in Example 3. Even if themulti-color light emission apparatus was allowed to stand in theatmosphere for two weeks, the multi-color light emission apparatusmaintained uniform light emission without changes in luminance andchromaticity coordinate and also without dark spots as deterioration ofthe device progressed. Also, the angle of view defined by the range inwhich leakage of light (mono-chromatic light) emitted from the organicelectroluminescence device was not confirmed was ±70° which was apractical level.

Also, because the transparent substrate was laminated, the fluorescentlayer was never damaged even if the fluorescent layer was contacted by anail and the handling, such as carrying of the apparatus, was easy.

Comparative Example 1

First, a substrate A was manufactured in the same manner as in Example1.

Next, characters EL with a width of 1 mm were printed on the transparentsubstrate with dimension of 25 mm×75 mm×1.1 mm (thickness) within theportion corresponding to the crossed portion (a range of 10 mm×55 mm) ofan electrode and a transparent electrode through a screen board using anink (viscosity 8,000 cp) produced by dissolving coumarin 6/polyvinylchloride resin (molecular weight 20,000) in cyclohexanone in thecoumarine 6 concentration of 0.03 mol/kg (film). The characters wereair-dried to prepare a fluorescent pattern of the characters EL to forma substrate E.

The substrate E was applied to the above substrate A so that thefluorescent layer of the substrate E faced the organic EL device and theadhesive was cured. After that, hydrocarbon fluoride (Fluorinert,manufactured by Sumitomo 3M Corp.) was injected under a nitrogenatmosphere using an injection needle, through slits in the curedadhesive into a gap between the support substrate (substrate A) and theapplied substrate (substrate E). Then, the same adhesive was filled intothe slits in the cured adhesive and cured.

A multi-color light emission apparatus composed of the organic EL devicewas manufactured in this manner as shown in FIG. 7. When a d.c. voltageof 8 V was applied between the transparent electrode (anode) and theelectrode (cathode) of the multi-color light emission apparatus, thecrossed portions of the transparent electrodes and the electrodesemitted light. The luminance and chromaticity coordinates of each lightviewed from the portion lacking the fluorescent layer and from thecharacters EL were the same as those in Example 1.

However, when the multi-color light emission apparatus was allowed tostand in the atmosphere for two weeks, the luminance of the blue lightemitting portion decreased to 5 cd/m² and the luminance of the lightviewed from the characters EL decreased to 7 cd/m². Also, dark spots,appearing as deterioration of the device progressed, increased,resulting in nonuniform light emission. It was confirmed that when thefluorescent layer is disposed so as to face the organic EL devicecontrary to Example 1, the light emission life of the multi-color lightemission apparatus was greatly impaired.

Comparative Example 2

A substrate C was manufactured in the same manner as in Example 3.

A transparent inorganic oxide substrate (borosilicate glass) (substrateF) of 100 mm×100 mm×0.30 mm thickness was applied to the above substrateC. Then, a multi-color light emission apparatus composed of an organicEL device (dot matrix type) shown in FIG. 4 was formed in the samemanner as in Example 3.

This multi-color light emission apparatus was allowed to emit light toresult in obtaining the same luminance and chromaticity as in Example 3.

When the multi-color light emission apparatus was allowed to stand inthe atmosphere for two weeks, the multi-color light emission apparatusmaintained uniform light emission without changes in luminance andchromaticity coordinates and also without dark spots appearing asdeterioration of the device progressed. However, the angle of viewdefined by the range in which leakage of light (mono-chromatic light)emitted from the organic electroluminescence device was not confirmedwas ±30°, so that there were portions (angles) where the light colorviewed from a normal sight range differed from the emitted light color,exhibiting a problem in practical use.

Example 6

A pattern of a fluorescent layer A with a thickness of 15 μm was printedby screen printing on a glass substrate (7059, manufactured by CorningCo., Ltd.) of 100 mm×100 mm×1.1 mm (thickness) as a transparent supportsubstrate using an ink (viscosity 8,000 cp) produced by dissolvingcoumarin 6/polyvinyl chloride resin (molecular weight 20,000) incyclohexanone in the coumarin 6 concentration of 0.03 mol/kg (film)through a screen board which enabled a stripe pattern of 1.4 mm linesand 3.1 mm gaps to be formed, followed by baking at 120° C. Next, apattern of a fluorescent layer B with a thickness of 20 μm were printedby screen printing on the substrate using an ink (viscosity 8,000 cp)produced by dissolving 43% (for film) by weight of a pigment containingrhodamine/polyvinyl chloride resin (molecular weight 20,000) incyclohexanone through a screen board which enabled a stripe pattern of1.4 mm lines and 3.1 mm gaps to be formed after lifting the pattern 1.5mm from the pattern of the fluorescent layer A in a directionperpendicular to the stripe, followed by baking at 120° C.

An aqueous solution of 20% by weight of polyvinyl alcohol (molecularweight 50,000) was applied to the entire substrate provided with thepatterns of the fluorescent layers by spin-coating. The substrate wasbaked at 80° C. to prepare a transparent protective layer of thefluorescent layers with a thickness of 5 μm.

Next, a photocurable transparent adhesive of epoxy type oligomer (3102,manufactured by Three Bond corp.) was applied to the protective layer bycasting. The glass surface of a glass plate (borosilicate glass) of 100mm×100 mm×50 μm thickness as an insulating inorganic oxide layer, onwhich a film of a transparent electrode (anode) of ITO (indium oxide ortin oxide) with a thickness of 0.12 μm and a surface resistance of 20Ω/□ was formed, was applied to the protective layer. The substrate wasirradiated with UV light through the ITO surface at a dose of 3,000mJ/cm² (365 nm), followed by baking at 80° C.

A film of a novolak/quinonediazido type positive resist (HPR 204,manufactured by Fuji Hunt Electronics Technology Co., Ltd.) waslaminated by spin-coating. After baking at 80° C., the substrate wasplaced on a proximity type exposure machine. Then, the substrate wasirradiated with light at a dose of 100 mJ/cm² (365 nm) using a maskcapable of transferring a stripe pattern of 1.2 mm lines and 0.3 mm gapsafter aligning the mask with the fluorescent layers A and B.

The resist on the substrate was developed using an aqueous solution of2.38% by weight of TMAH (Tetra-Methyl Ammonium Hydroxide) and post-bakedat 130° C. Then, the exposed ITO film was treated by etching usingaqueous hydrobromic acid and, finally, the positive type resist waspeeled off to prepare a pattern of the ITO film which constitutes ananode of the organic EL device.

Next, this substrate was washed with IPA and further irradiated with UVlight. Then, the substrate was secured to a substrate holder of a vapordeposition unit (manufactured by ULVAC Corporation). As materials forvapor deposition, MTDATA and NPD for a positive hole injecting layer,DPVBi for anemittingmaterial, andAlq for an electron injecting layer,were placed in a resistance heating molybdenum boat. Ag as a secondmetal for an electrode (cathode) was attached to a tungsten filament,and Mg as an electron injecting metal for an electrode (cathode) wasattached to the molybdenum boat.

After that, the pressure in a vacuum vessel was reduced to 5×10⁻⁷ torrand then the above materials were sequentially laminated in thefollowing order. A vacuum was maintained during the steps between thestep of forming the positive hole injecting layer and the step offorming the cathode by one evacuating operation. First, a positive holeinjecting layer was formed by depositing MTDATA at a vapor depositionrate of 0.1-0.3 nm/s to a film thickness of 200 nm and also depositingNPD at a vapor deposition rate of 0.1-0.3 nm/s to a film thickness of 20nm. Next, an emitting layer was formed by depositing DPVBi at a vapordeposition rate of 0.1-0.3 nm/s to a film thickness of 50 nm. Then, anelectron injecting layer was formed by depositing Alq at a vapordeposition rate of 0.1-0.3 nm/s to a film thickness of 20 nm. Finally,Mg and Ag were vapor-deposited simultaneously as the cathode at vapordeposition rates of 1.3-1.4 nm/s and 0.1 nm/s respectively to a filmthickness of 200 nm through a mask capable of transferring a stripepattern of 4 mm lines and 0.5 mm gaps which is perpendicular to thestripe pattern of the anode composed of ITO.

A multi-color light emission apparatus composed of the organic EL devicewas manufactured in this manner as shown in FIG. 11. When a d.c. voltageof 8 V was applied between the anode and the cathode of the multi-colorlight emission apparatus, the crossed portions of the anodes andcathodes emitted light. The luminance of the light viewed from theportion lacking the fluorescent layer was 100 cd/m². The CIEchromaticity coordinate (JIS Z 8701) was as follows: x=0.15, y=0.15.Light of a blue color was detected.

On the other hand, the luminance of the light viewed from thefluorescent layer A was 120 cd/m² and the CIE chromaticity coordinateswere as follows: x=0.28, y=0.62. Light of a yellowish green color wasdetected.

Also, the luminance of the light viewed from the fluorescent layer B was30 cd/m² and the CIE chromaticity coordinates were as follows: x=0.60,y=0.31. Light of a red color was detected.

The multi-color light emission apparatus manufactured in the abovemanner was allowed to stand under a nitrogen stream for two weeks. As aresult, the multi-color light emission apparatus maintained uniformlight emission without changes in luminance and chromaticity coordinatesand also without dark spots appearing as deterioration of the deviceprogressed. Also, the angle of view defined by the range in whichleakage of light (mono-chromatic light) emitted from the organic ELdevice was not confirmed was 60°, which was a practical level.

The water content of the glass substrate with a thickness of 50 μm was0.1% by weight or less and the gas permeability of the glass substratefor aqueous vapor and for oxygen was 10⁻¹³ cccm/cm² scmHg or less.

Example 7

A photocurable transparent adhesive of epoxy type oligomer (3112,manufactured by Three Bond corp.) was applied, by casting, to thesubstrate provided with the fluorescent layers A and B, which wasprepared in Example 6. The glass surface of a glass plate (borosilicateglass) of 100 mm×100 mm×50 μm thickness as an insulating inorganic oxidelayer on which a film of a transparent electrode (anode) of ITO with athickness of 0.12 μm and a surface resistance of 20 Ω/□ was formed wasapplied to the substrate. The substrate was irradiated with UV raysthrough the surface of ITO at a dose of 3,000 mJ/cm² (365 nm), followedby baking at 80° C.

Then, the ITO was patterned and an organic EL device was formed underthe same conditions as in Example 6 to prepare a multi-color lightemission apparatus composed of the organic EL device shown in FIG. 10.

This multi-color light emission apparatus was allowed to emit light toobtain the same luminance and chromaticity coordinates as in Example 6.When the multi-color light emission apparatus was allowed to stand undera nitrogen stream for two weeks, it maintained uniform light emissionwithout changes in luminance and chromaticity coordinate and alsowithout dark spots as deterioration of the device progressed. Also, theangle of view defined by the range in which leakage of light(mono-chromatic light) emitted from the organic electroluminescencedevice was not confirmed was ±55°, which was a practical level.

Example 8

A photocurable resist containing carbon black (CK 2000, manufactured byFuji Hunt Electronics Technology Co., Ltd.) was applied by spin-coatingto a glass substrate (7059, manufactured by Corning Co., Ltd.) of 100mm×100 mm×1.1 mm (thickness) as a transparent support substrate, whichwas baked at 80° C. Then, an oxygen shielding film of polyvinylalcohol(CP, manufactured by Fuji Hunt Electronics Technology Co., Ltd.)was formed on the substrate by spin-coating, and was baked at 80° C.Next, the resulting substrate was placed on a proximity type exposuremachine. The substrate was then irradiated with light at a dose of 100mJ/cm² (365 nm) using a mask capable of transferring a stripe pattern of0.3 mm lines and 1.2 mm gaps. The resist on the substrate was developedusing aqueous 1N sodium carbonate solution and post-baked at 200° C. toprovide a black matrix.

A photocurable resist containing copper phthalocyanine (CB 2000,manufactured by Fuji Hunt Electronics Technology Co., Ltd.) was appliedto the substrate by spin-coating and was baked at 80° C. Then, an oxygenshielding film of polyvinyl alcohol (CP, manufactured by Fuji HuntElectronics Technology Co., Ltd.) was formed on the substrate byspin-coating and was baked at 80° C. Next, the substrate was placed on aproximity type exposure machine. The substrate was then irradiated withlight at a dose of 100 mJ/cm² (365 nm) using a mask capable oftransferring a stripe pattern of 1.4 mm lines and 3.1 mm gaps afteraligning the substrate so that the pattern was embedded in gaps of theblack matrix. The resist on the substrate was developed using aqueous 1Nsodium carbonate solution and post-baked at 200° C. to provide a bluecolor filter.

Fluorescent layers A and B were printed by screen printing on portionsother than the blue color filter of the substrate provided with theblack matrix and the blue color filter under the same conditions as inExample 1 after alignment with the gaps of the black matrix. Then, thesame glass plate as in Example 1, specifically, a glass plate with athickness of 50 μm, which was provided with a film of ITO (anode), wasapplied to the above substrate to form an ITO pattern.

Next, this substrate was washed with IPA and further irradiated with UVlight. Then, the substrate was secured to a substrate holder of a vapordeposition unit (manufactured by ULVAC Corporation). As materials forvapor deposition, MTDATA and NPD for a positive hole injecting layer,DPVBi for an emitting material, DPAVB for a dopant, and Alq for anelectron injecting layer were placed in a resistance heating molybdenumboat. Ag as a second metal for an electrode (cathode) was attached to atungsten filament, and Mg as an electron injecting metal for anelectrode (cathode) was attached to the molybdenum boat.

After that, the pressure in the vacuum vessel was reduced to 5×10⁻⁷ torrand the above materials were sequentially laminated in the followingorder. A vacuum was maintained during the steps between the step offorming the positive hole injecting layer and the step of forming thecathode by one evacuating operation. First, a positive hole injectinglayer was formed by depositing MTDATA at a vapor deposition rate of0.1-0.3 nm/s to a film thickness of 200 nm and also depositing NPD at avapor deposition rate of 0.1-0.3 nm/s to a film thickness of 20 nm.Then, an emitting layer was formed by depositing DPVBi at a vapordeposition rate of 0.1-0.3 nm/s and also depositing DPAVB at a vapordeposition rate of 0.05 nm/s to a total film thickness of 40 nm (theproportion by weight of dopant to host material was from 1.2 to 1.6).Then, an electron injecting layer was formed by depositing Alq at avapor deposition rate of 0.1-0.3 nm/s to a film thickness of 20 nm.Finally, Mg and Ag were simultaneously vapor-deposited as the cathode atvapor deposition rates of 1.3-1.4 nm/s and 0.1 nm/s respectively to afilm thickness of 200 nm through a mask capable of transferring a stripepattern of 4 mm lines and 0.5 mm gaps which is perpendicular to thestripe pattern of the ITO anode.

A multi-color light emission apparatus composed of the organic EL devicewas manufactured in this manner as shown in FIG. 13. When a d.c. voltageof 8 V was applied between the anode and the cathode of the multi-colorlight emission apparatus, the crossed portions of the anodes andcathodes emitted light. The luminance of the light viewed from the bluecolor filter was 35 cd/m². The CIE chromaticity coordinates (JIS Z 8701)were as follows: x=0.14, y=0.12. Light of a blue color was detected.

On the other hand, the luminance of the light viewed from thefluorescent layer A was 120 cd/m² and the CIE chromaticity coordinateswere as follows: x=0.28, y=0.62. Light of a yellowish green color wasdetected.

Also, the luminance of the light viewed from the fluorescent layer B was30 cd/m² and the CIE chromaticity coordinates were as follows: x=0.60,y=0.31. Light of a red color was detected.

The multi-color light emission apparatus manufactured in the abovemanner was allowed to stand under a nitrogen stream for two weeks. As aresult, the multi-color light emission apparatus maintained uniformlight emission without changes in luminance and chromaticity coordinateand also without dark spots appearing as deterioration of the deviceprogressed. Also, the angle of view defined by the range in which colormixing was not confirmed when mono-chromatic light was emitted was ±70°,which was a practical level.

Example 9

A methacrylate type photocurable resin (V259PA, manufactured by NipponSteel Chemical Co., Ltd.) was applied, by spin-coating, to the substrateprovided with the fluorescent layers A and B, which was prepared inExample 6. After baking at 80° C., the substrate was irradiated with UVlight at a dose of 300 mJ/cm² (365 nm). Then, the substrate was baked at160° C. to laminate a transparent protective layer with a thickness of 5μm.

Next, a silicon oxide film as as insulating inorganic oxide layer with athickness of 0.01 μm was laminated over the entire substrate heated at160° C. using a sputtering apparatus. Then, a film of ITO (anode) with athickness of 0.12 μm and a surface resistance of 20 Ω/□ was formed onthe substrate using a sputtering apparatus, while the substrate washeated at 160° C.

Then, the ITO was patterned and an organic EL device was formed underthe same conditions as in Example 6 to prepare a multi-color lightemission apparatus composed of the organic EL device shown in FIG. 12.This multi-color light emission apparatus was allowed to emit light toobtain the same luminance and chromaticity coordinates as in those inExample 6. When the multi-color light emission apparatus was allowed tostand under a nitrogen stream for two weeks, the multi-color lightemission apparatus maintained uniform light emission with almost nochanges in luminance and chromaticity coordinates and also with few darkspots appearing as deterioration of the device progressed. Also, theangle of view defined by the range in which leakage of light(mono-chromatic light) emitted from the organic electroluminescencedevice was not confirmed was ±90°, which was a practical level.

The water content of the silicon oxide film with a thickness of 0.01 μmwas 0.1% by weight or less and the gas permeability of the silicon oxidefilm for aqueous vapor and for oxygen was 10⁻¹³ cccm/cm² scmHg or less.

Example 10

An aluminum oxide film as an insulating inorganic oxide layer with athickness of 0.01 μm was laminated over the entire substrate providedwith the fluorescent layers A and B, which was prepared in Example 6,using a sputtering apparatus while heating the substrate at 160° C.Then, a solid film of ITO with a thickness of 0.12 μm and a surfaceresistance of 20 Ω/□ was formed on the substrate using a sputteringapparatus, while the substrate was heated at 160° C.

Then, the ITO was patterned and an organic EL device was formed underthe same conditions as in Example 6 to prepare a multi-color lightemission apparatus composed of the organic EL device shown in FIG. 9.This multi-color light emission apparatus was allowed to emit light toobtain the same luminance and chromaticity coordinates as in those inExample 6. When the multi-color light emission apparatus was allowed tostand under a nitrogen stream for two weeks, the multi-color lightemission apparatus maintained uniform light emission with almost nochanges in luminance and chromaticity coordinate and also with few darkspots appearing as deterioration of the device progressed. Also, theangle of view defined by the range in which leakage of light(mono-chromatic light) emitted from the organic electroluminescencedevice was not confirmed was ±90°, which was a practical level.

The water content of the aluminum oxide film with a thickness of 0.01 μmwas 0.1% by weight or less and the gas permeability of the aluminumoxide film for aqueous vapor and for oxygen was 10⁻¹³ cccm/cm² scmHg orless.

Example 11

A titanium oxide film as an insulating inorganic oxide layer with athickness of 0.01 μm was laminated by sputtering over the entiresubstrate provided with the fluorescent layers A and B, which wasprepared in Example 6, while heating the substrate at 160° C. Then, asolid film of ITO with a thickness of 0.12 μm and a surface resistanceof 20 Ω/□ was formed on the substrate using a sputtering apparatus,while the substrate was heated at 160° C.

Then, the ITO was patterned and an organic EL device was formed underthe same conditions as in Example 6 to prepare a multi-color lightemission apparatus composed of the organic EL device shown in FIG. 9.This multi-color light emission apparatus was allowed to emit light toobtain the same luminance and chromaticity coordinates as in those inExample 6. When the multi-color light emission apparatus was allowed tostand under a nitrogen stream for two weeks, the multi-color lightemission apparatus maintained uniform light emission with almost nochanges in luminance and chromaticity coordinates and also with few darkspots appearing as deterioration of the device progressed. Also, theangle of view defined by the range in which leakage of light(mono-chromatic light) emitted from the organic electroluminescencedevice was not confirmed was ±90°, which was a practical level.

The water content of the titanium oxide film with a thickness of 0.01 μmwas 0.1% by weight or less and the gas permeability of the titaniumoxide film for aqueous vapor and for oxygen was 10⁻¹³ cccm/cm² scmHg orless.

Example 12

A photocurable transparent adhesive of a methacrylate type oligomer(3102, manufactured by 3-Bond corp.) was applied, by casting, to thesubstrate prepared in Example 6, in which the protective layer waslaminated on the fluorescent layers A and B. The glass surface of aglass substrate (soda-lime glass) of 100 mm×100 mm×50 μm thickness as aninsulating inorganic oxide layer on which a titanium oxide film with athickness of 0.05 μm and a film of a transparent electrode of ITO(anode) with a thickness of 0.12 μm were completely formed in order wasapplied to the substrate. The substrate was irradiated with UV raysthrough the surface of the ITO at a dose of 3,000 mJ/cm² (365 nm),followed by baking at 80° C.

Then, the ITO was patterned and an organic EL device was formed underthe same conditions as in Example 6 to prepare a multi-color lightemission apparatus composed of the organic EL device shown in FIG. 14.This multi-color light emission apparatus was allowed to emit light toobtain the same luminance and chromaticity coordinate as in those inExample 6. When the multi-color light emission apparatus was allowed tostand under a nitrogen stream for two weeks, the multi-color lightemission apparatus maintained uniform light emission with almost nochanges in luminance and chromaticity coordinate and also with few darkspots appearing as deterioration of the device progressed. Also, theangle of view defined by the range in which leakage of light(mono-chromatic light) emitted from the organic electroluminescencedevice was not confirmed was ±60°, which was a practical level.

The water content of the glass substrate with a thickness of 50 μm, onwhich the titanium oxide film with a thickness of 0.01 μm was formed, inthis example, was 0.1% by weight or less and the gas permeability of theglass substrate, on which titanium oxide film was formed, for aqueousvapor and for oxygen was 10⁻¹³ cccm/cm² scmHg or less.

Comparative Example 3 (in the case of no provision for the inorganicoxide layer)

A methacrylate type photocurable resin (V259PA, manufactured by NipponSteel Chemical Co., Ltd.) was applied, by spin-coating, to the substrateprovided with the fluorescent layers A and B, which was prepared inExample 6. After baking at 80° C., the substrate was irradiated with UVlight at a dose of 300 mJ/cm² (365 nm). Then, the substrate was baked at160° C. to laminate a transparent protective layer with a thickness of 5μm.

Next, a film of ITO (anode) with a thickness of 0.12 μm and a surfaceresistance of 20 Ω/□ was formed on the substrate using a sputteringapparatus, while the substrate was heated at 160° C.

Then, the ITO was patterned and an organic EL device was formed underthe same conditions as in Example 6 to prepare a multi-color lightemission apparatus composed of the organic EL device shown in FIG. 15.This multi-color light emission apparatus was allowed to emit light toobtain the same luminance and chromaticity as in those in Example 6.However, when the multi-color light emission apparatus was allowed tostand under a nitrogen stream for two weeks, the luminance viewed fromthe portion lacking the fluorescent layer under the same conditions asin Example 6 decreased to 5 cd/cm² and many dark points as deteriorationof the device progressed, exhibiting a clear problem.

The total content of water contained in the protective layer was 1.2% byweight and the gas permeability of the protective layer for aqueousvapor and for oxygen was 10⁻¹³ cccm/cm² scmHg or more.

Comparative Example 4 (in the case where the thickness of the inorganicoxide layer was 0.005 μm)

A methacrylate type photocurable resin (V259PA, manufactured byNipponSteel Chemical Co., Ltd.) was applied, by spin-coating, to the substrateprovided with the fluorescent layers A and B, which was prepared inExample 6. After baking at 80° C., the substrate was irradiated with UVlight at a dose of 300 mJ/cm² (365 nm). Then, the substrate was baked at160° C. to laminate a transparent protective film with a thickness of 5μm.

Next, using a sputtering apparatus, a silicon oxide film as aninsulating inorganic oxide layer with a thickness of 0.005 μm waslaminated over the entire substrate heated at 160° C. and a solid filmof ITO with a thickness of 0.12 μm and a surface resistance of 20 Ω/□was formed over the entire substrate using a sputtering apparatus, whilethe substrate was heated at 160° C.

Then, the ITO was patterned and an organic EL device was formed underthe same conditions as in Example 6 to prepare a multi-color lightemission apparatus composed of the organic EL device. This multi-colorlight emission apparatus was allowed to emit light to obtain the sameluminance and chromaticity as in Example 6. However, when themulti-color light emission apparatus was allowed to stand under anitrogen stream for two weeks, the luminance viewed from the portionlacking the fluorescent layer under the same conditions as in Example 6decreased to 20 cd/cm² and many dark spots as deterioration of thedevice progressed, exhibiting a clear problem.

The water content of the silicon oxide film with a thickness of 0.005 μmwas 0.1% by weight or less. However, the gas permeability of the siliconoxide film with a thickness of 0.005 μm for aqueous vapor and for oxygenwas 10⁻¹³ cccm/cm² scmHg or more.

Comparative Example 5 (in the case where the thickness of the inorganicoxide layer (plate glass) was 300 μm)

The glass surface of a glass plate (borosilicate glass) of 100 mm×100mm×300 μm thickness as an insulating inorganic oxide layer on which asolid film of ITO (anode) with a thickness of 0.12 μm and a surfaceresistance of 20 Ω/□ was formed was applied to the substrate prepared inExample 6, on which the patterns of the fluorescent layers A and B, theprotective layer, and the adhesive layer were subsequently laminated.The substrate was irradiated with UV rays through the ITO surface at adose of 3,000 mJ/cm² (365 nm), followed by baking at 80° C.

Then, the ITO was patterned and an organic EL device was formed underthe same conditions as in Example 6 to prepare a multi-color lightemission apparatus composed of the organic EL device. This multi-colorlight emission apparatus was allowed to emit light to obtain the sameluminance and chromaticity as in Example 6. When the multi-color lightemission apparatus was allowed to stand under a nitrogen stream for twoweeks, the multi-color light emission apparatus maintained uniform lightemission with almost no changes in luminance and chromaticitycoordinates and also with few dark points appearing with the progress indeterioration of the device. However, the angle of view defined by therange in which leakage of light (mono-chromatic light) emitted from theorganic EL device was not confirmed was ±30°. There were portions(angles) where light of a color differing from the emitted color wasviewed in a normal sight range, exhibiting a practical problem.

Comparative Example 6 (in the case of forming the protective layer (flatlayer) using a sol-gel glass method)

The substrate produced in Example 6, which was provided with thepatterns of the fluorescent layers A and B, was dipped into a mixedsolution consisting of 10% by weight of tetraethoxysilane (Si(OC₂ H₅)₄)and water/ethanol (ratio by volume: 1:2) containing 1% by weight ofhydrochloric acid.

The substrate was slowly lifted to produce a substrate in which thefluorescent layers A and B were dip-coated with silicon oxide (SiO₂)sol.

The substrate was then heated at 400° C. so that silicon oxide wasallowed to gel and thereby a glass-like protective layer was laminatedon the fluorescent layers A and B. However, it was confirmed that thepatterns of the fluorescent layers A and B were blackened (carbonized)to show deterioration in these layers.

Because of this, the substrate was heated at 160° C. so that siliconoxide was allowed to gel and thereby a glass-like protective layer witha thickness of 0.2 μm was laminated on the fluorescent layers A and B.

Next, a film of ITO (anode) with a thickness of 0.12 μm and a surfaceresistance of 20 Ω/□ was formed on the entire substrate using asputtering apparatus, while the substrate was heated at 160° C.

Then, the ITO was patterned and an organic EL device was formed underthe same conditions as in Example 6 to provide a multi-color lightemission apparatus composed of the organic EL device shown in FIG. 15.This multi-color light emission apparatus was allowed to emit light toobtain the same luminance and chromaticity as in Example 6. However,when the multi-color light emission apparatus was allowed to stand undera nitrogen stream for two weeks, the luminance viewed from the portionlacking the fluorescent layer under the same conditions as in Example 6decreased to 5 cd/cm² and many dark spots appeared as deterioration ofthe device progressed, exhibiting a clear problem.

The water content contained in the sol-gel silicon oxide film with athickness of 0.2 μm was 1.5% by weight. Also, the gas permeability ofthe sol-gel silicon oxide film to aqueous vapor and to oxygen was 10⁻¹³cccm/cm² scmHg or more, showing that the protective layer produced bythe sol-gel method was inappropriate.

INDUSTRIAL APPLICABILITY

As is clear from the above explanations, the present invention canprovide a multi-color light emission apparatus using an organic ELdevice having an excellent light emission life and excellentcharacteristics in the angle of view. Also, the present invention canprovide a process for manufacturing the multi-color light emissionapparatus in a stable and efficient manner.

Accordingly, the present invention can be preferably applied for thintype multi-color or full color displays of various emission types.

What is claimed is:
 1. A multi-color light emission apparatus comprisinga support substrate, an organic electroluminescence (EL) device disposedon the support substrate, and a fluorescent layer disposed to correspondto a transparent electrode or electrode of the organic EL device toabsorb the light emitted from the organic EL device and to emit visiblefluorescent light, wherein a transparent inorganic oxide substrate onwhich the fluorescent layer is placed is disposed between the organic ELdevice and the fluorescent layer in such a manner as to provide a gapbetween the fluorescent layer and the organic EL device, and the organicEL device is sealed using a sealing means between the transparentinorganic oxide substrate and the support substrate.
 2. The multi-colorlight emission apparatus according to claim 1, wherein the fluorescentlayer is separately disposed on the transparent inorganic oxidesubstrate on the same plane.
 3. The multi-color light emission apparatusaccording to claim 1 or 2,wherein at least a transparent protectivelayer of the fluorescent layer and a transparent substrate are fartherdisposed on the fluorescent layer.
 4. The multi-color light emissionapparatus according to claim 1, wherein the thickness of the transparentinorganic oxide substrate is in a range of from 1 to 200 μm.
 5. Themulti-color light emission apparatus according to claim 1, wherein thetransparent inorganic oxide substrate is made of a transparent glassplate.
 6. A multi-color light emission apparatus comprising atransparent support substrate, fluorescent layers separately disposed onthe transparent support substrate on the same plane, and an organicelectroluminescence (EL) device disposed on or above the fluorescentlayers, the fluorescent layers being disposed to correspond to atransparent electrode or electrode of the organic EL device so that eachof the fluorescent layers absorbs the light emitted from the organic ELdevice and emits different visible fluorescent light, wherein atransparent and insulating inorganic oxide layer with a thickness offrom 0.01 to 200 μm is interposed between the fluorescent layer and theorganic EL device wherein at least a transparent protective layer of thefluorescent layers and a transparent adhesive layer are disposed betweenthe fluorescent layers and the transparent and insulating inorganicoxide layer.
 7. The multi-color light emission apparatus according toclaim 6, wherein the transparent and insulating inorganic oxide layer ismade of a transparent and insulating glass plate.
 8. The multi-colorlight emission apparatus according to claim 6, wherein the transparentinorganic oxide layer is made from one or more compounds selected from agroup consisting of silicon oxide, aluminum oxide, and titanium oxide.9. The multi-color light emission apparatus according to claim 6,wherein the transparent and insulating inorganic oxide layer is producedby forming a film of one or more compounds selected from a groupconsisting of silicon oxide, aluminum oxide, and titanium oxide on atleast one of the surface or back face of a transparent and insulatingglass plate.
 10. The multi-color light emission apparatus according toclaim 6, wherein the transparent and insulating inorganic layer containsmainly an inorganic oxide.